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description Publicationkeyboard_double_arrow_right Article 2023 United KingdomPublisher:Elsevier BV Hossein Yazdi; Hamid Reza Ghafari; Hassan Ghassemi; Guanghua He; Madjid Karimirad;Integrating a floating offshore wind turbine (FOWT) and an array of wave energy converters (WECs) can be suggested as a proper new hybrid concept with the aim of more energy harvesting and lower total energy cost. This paper proposes the new composition of a floating braceless semi-submersible platform and an array of Salter's duck (SD) WECs. First, a comparison of the numerical results and experimental data of the hydrodynamics response of FOWT and the single SD WEC response are presented and discussed. Then, the performance of three-hybrid FOWT-Multi-Salter's Duck (FOWT-MSD) systems with 12SD, 15SD, and 18SD WECs has been investigated under different wave periods and wave heights. In the wave period of 6–9 s, 12SD absorbs more power than 15SD and 18SD. From T = 9–11 s, all three systems have the same absorbed power. For wave periods above 12 s, 15SD and 18SD have higher absorbed power than 12SD. No clear trend was observed for wave periods below 6 s. The effect of wave direction shows that at lower wave heights, maximum absorber power belongs to FOWT-12SD under zero wave direction. In contrast, increasing wave heights leads to a smaller difference between the three-hybrid systems at different wave directions.
Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2023.127930&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen 29 citations 29 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2023.127930&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012Publisher:Elsevier BV Authors: Torgeir Moan; Madjid Karimirad;AbstractThe feasibility of the application of a spar-type wind turbine at a moderate water depth is studied in this paper. In the oil and gas industries, spar-type offshore platforms are widely applied in deep water. The same idea is used in offshore wind technology to present the Hywind concept based on a catenary moored spar in deep water. The draft of the spar limits the application of spar-type wind turbines in shallow water. However, it is possible to design spar-type wind turbines for moderate water depths. The present article studies the feasibility and performance of such a design. A spar-type wind turbine at a moderate water depth called “ShortSpar” is introduced in the present article. A catenary moored spar-type support structure is applied as a base for the 5-MW NREL land-based turbine. The power performance, structural integrity and dynamic responses of a 5-MW catenary moored spar-type wind turbine in deep water (DeepSpar) have previously been studied. In the present article, the responses of the spar-type wind turbines, ShortSpar and DeepSpar, are compared. The HAWC2 code is used to carry out the coupled aero-hydro-servo-elastic analyses. Different environmental conditions are used to compare the responses. A dynamic link library (DLL) is used to feed the mooring forces at each time step into the HAWC2 code. The force-displacement relationships are obtained from the Simo-Riflex code. The comparison of the responses of ShortSpar and DeepSpar in different load cases indicates the feasibility of implementation of spar-type wind turbine in moderate water depths. The results show that the spar-type wind turbine at a moderate water depth exhibits good performance, and its responses are reasonable compared with those associated with a spar-type wind turbine in deep water. The total mass (the structural mass plus the ballast) of ShortSpar is 35% less than the mass of DeepSpar, while the statistical characteristics of the generated power are almost the same for both spars. This mass reduction for ShortSpar helps to achieve a more cost-effective solution for floating wind turbines at a moderate water depth.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2012.06.117&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 25 citations 25 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2012.06.117&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012Publisher:American Society of Civil Engineers (ASCE) Authors: Madjid Karimirad; Torgeir Moan;This paper addresses coupled wave and wind-induced motions of spar-type 5-MW wind turbines in harsh and operational environmental conditions. Global dynamic motion responses have been analyzed by aero-hydro-servo-elastic time-domain simulations. The aerodynamics is based on an advanced blade element momentum theory. Panel method and Morison formula accounting for the instantaneous position of the structure are applied for hydrodynamics. Hydrodynamic drag and considering geometrical updating introduce nonlinearities. Hydrodynamic nonlinearities were found to cause excitation of the natural frequencies in the low frequency range more than in the wave frequency range. Extrapolation methods are applied to estimate the maximum responses. A previous study showed that the uncertainty of such an extrapolation for the present concept is less than 2%. In this study it is found that the mean values of the dynamic responses are primarily wind induced and the standard deviations of the responses are primarily wave ind...
Journal of Waterway ... arrow_drop_down Journal of Waterway Port Coastal and Ocean EngineeringArticle . 2012 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1061/(asce)ww.1943-5460.0000087&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu117 citations 117 popularity Top 1% influence Top 1% impulse Top 1% Powered by BIP!
more_vert Journal of Waterway ... arrow_drop_down Journal of Waterway Port Coastal and Ocean EngineeringArticle . 2012 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1061/(asce)ww.1943-5460.0000087&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 United KingdomPublisher:Wiley Authors: Karimirad, Madjid; Moan, Torgeir;doi: 10.1002/we.1537
ABSTRACTThis paper presents a stochastic dynamic response analysis of a tension leg spar‐type wind turbine subjected to wind and wave actions. The dynamic motions, structural responses, power production and tension leg responses are analyzed. The model is implemented using the HAWC2 code. Several issues such as negative damping, rotor configuration (upwind or downwind rotor) and tower shadow effects are discussed to study the power performance and structural integrity of the system. The operational and survival load cases considering the stochastic wave and wind loading are analyzed to investigate the functionality of the tension leg spar‐type wind turbine. Amelioration of the negative damping applied for this concept reduces the structural dynamic responses, which are important for fatigue life. It is found that the responses induced by wave and wind actions at the wave frequencies are not affected much by the aerodynamic excitation or damping forces. Because of the nonlinear effects of the tension leg, all of the motion responses are strongly coupled. The global responses of upwind and downwind versions of the turbine are found to be close because the tower shadow has a limited effect on the global responses. However, the structural dynamic responses of the blades are more affected by the tower shadow. In this study, the extrapolation methods are applied to efficiently estimate the maximum responses. The maximum response is found to occur in the survival cases as a result of the wave actions and the increased aerodynamic drag forces on the tower. The results show that the maximum responses corresponding to the up‐crossing rate of 0.0001 (corresponding to the maximum response within a 3 hour period) can be expressed by the mean plus 3 to 5 standard deviations. Copyright © 2012 John Wiley & Sons, Ltd.
Wind Energy arrow_drop_down Wind EnergyArticle . 2012 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2013Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1002/we.1537&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 26 citations 26 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Wind Energy arrow_drop_down Wind EnergyArticle . 2012 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2013Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1002/we.1537&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2015 United KingdomPublisher:Elsevier BV Authors: Karimirad, Madjid; Michailides, Constantine;AbstractThe development of cost effective floating type offshore wind turbines has been desired in deep sea areas. Semisubmersible platform can be considered as a very efficient design configuration among the different type proposed floating platforms. In the present paper, a preliminary assessment of the dynamic behavior of a 5-MW braceless semisubmersible offshore wind turbine with three columns and two fully submerged pontoons is presented for selected environmental operational conditions that correspond to a deep water offshore site with depth 200 m. Hydro-aero-servo-elastic time domain analysis is performed with the use of the coupled analysis tool Simo-Riflex-AeroDyn in order to calculate the dynamic behavior and response of the offshore floating wind turbine. Statistical values and spectra of time histories of response quantities are presented. The results demonstrate the feasibility of the presented deep sea floating wind turbine concept.
Energy Procedia arrow_drop_down Queen's University Belfast Research PortalArticle . 2015Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2015.11.402&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 13 citations 13 popularity Top 10% influence Average impulse Average Powered by BIP!
more_vert Energy Procedia arrow_drop_down Queen's University Belfast Research PortalArticle . 2015Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2015.11.402&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2024 United KingdomPublisher:Elsevier BV Jie Fu; Xu Han; Wei Shi; Madjid Karimirad; Xin Li;Physical model-scale testing could assist in identifying important coupling effects and validating numerical simulations. However, the requirement regarding the dynamic similarity for the offshore wind turbine model is difficult to meet due to the scaling effects. To address this challenge, a testing method is proposed, using a linear actuator to reproduce the required aerodynamic force for the real-time hybrid model test. The magnitudes of the applied force were simulated using a numerical substructure developed based on the aerodynamic coupling analysis. This paper designed the physical substructure of offshore wind turbines, selected the "Hardware in the Loop" method, and conducted relevant experiments in a wave tank. The turbulent wind and pitch control were reproduced during the testing process. The experimental data and simulation results were compared and analyzed. The maximum error of the average values of different physical quantities (Rotor thrust force, Tower top displacement) measured was 5.51 %, while the maximum error in the standard values was −10.59 %. The data indicate good consistency between the experimental and simulation results. From the analysis of power spectral density (PSD) results of different physical quantities, it was found that turbulent wind provides significant excitation and energy in the frequency range below wave excitation. The frequency of turbulent wind loads hides the low-frequency second-order wave forces, indicating the necessity of reproducing turbulent winds in experiments. The real-time hybrid model test method can accurately reproduce the turbulent wind load, achieve the combined action of random wind and waves, and improve the model testing level of existing monopile offshore wind turbines.
Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104304&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!
more_vert Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104304&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2024 United KingdomPublisher:Elsevier BV Wei Shi; Jie Fu; Zhengru Ren; Madjid Karimirad; Huimeng Zhou; Xin Li;The real-time hybrid model (RTHM) test is adept at addressing the scale contradiction, the lack of fidelity in wind modelling in hydrodynamic testing facilities and spatial constraints inherent in conventional monopile-type offshore wind turbine (OWT) model testing methods, thus emerging as an effective avenue for conducting physical model tests of Monopile-type OWTs. This method entails the reproduction of aerodynamic loads or platform motions using loading device or vibration tables. Time delays in the physical attributes of the loading device and signal transmission processes within the system can result in error accumulation, with the potential to impact overall system stability. Moreover, time delay compensation algorithms for hybrid model test systems with force control loading can easily generate excessive noise, leading to system divergence. As a result, time delay has emerged as a technical challenge in the RTHM test. To address this issue, this paper has developed second-order and third-order polynomial extrapolation algorithms, alongside an adaptive compensation algorithm. The adaptive compensation algorithm employs the least squares method to identify parameters of the loading system, enabling it to address variations in the time delay of the experimental system caused by the nonlinearity of the loading system and changes in the physical properties of the model. The feasibility and effects of time delay compensation for various algorithms are validated through numerical simulation. Results indicate that the adaptive compensation algorithm surpasses second and third-order polynomial extrapolation compensation algorithms in terms of accuracy and compensation effectiveness. To validate the applicability of the adaptive compensation algorithm, a RTHM test was conducted. Across rotor thrust force (RotThrust) and tower top displacement, there was an average reduction of approximately 5% and 9% in the maximum and minimum synchronization errors, respectively. This highlights the efficacy of the delay compensation algorithm in practical applications, notably diminishing time delay errors within the experimental system. The adaptive compensation algorithm continuously adjusts and updates parameters, enhancing the adaptability of the compensation process to time-varying systems.
Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104234&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!
more_vert Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104234&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal , Other literature type 2020 United KingdomPublisher:MDPI AG Authors: Mohsen Sobhaniasl; Francesco Petrini; Madjid Karimirad; Franco Bontempi;doi: 10.3390/en13123096
In this paper, a procedure is proposed to determine the fatigue life of the electrical cable connected to a 5 MW floating offshore wind turbine, supported by a spar-buoy at a water depth of 320 m, by using a numerical approach that takes into account site-specific wave and wind characteristics. The effect of the intensity and the simultaneous actions of waves and wind are investigated and the outcomes for specific cable configurations are shown. Finally, the fatigue life of the cable is evaluated. All analyses have been carried out using the Ansys AQWA computational code, which is a commercial code for the numerical investigation of the dynamic response of floating and fixed marine structures under the combined action of wind, waves and current. Furthermore, this paper applies the FAST NREL numerical code for comparison with the ANSYS AQWA results.
Energies arrow_drop_down EnergiesOther literature type . 2020License: CC BYFull-Text: http://www.mdpi.com/1996-1073/13/12/3096/pdfData sources: Multidisciplinary Digital Publishing InstituteQueen's University Belfast Research PortalArticle . 2020Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.3390/en13123096&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 25 citations 25 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Energies arrow_drop_down EnergiesOther literature type . 2020License: CC BYFull-Text: http://www.mdpi.com/1996-1073/13/12/3096/pdfData sources: Multidisciplinary Digital Publishing InstituteQueen's University Belfast Research PortalArticle . 2020Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.3390/en13123096&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2023 United Kingdom, Italy, Sweden, SpainPublisher:Elsevier BV Bonaventura Tagliafierro; Madjid Karimirad; Corrado Altomare; Malin Göteman; Iván Martínez-Estévez; Salvatore Capasso; José M. Domínguez; Giacomo Viccione; Moncho Gómez-Gesteira; Alejandro J.C. Crespo;handle: 2117/403843 , 11386/4845651 , 11093/5275
In this work, we propose numerical validations of the DeepCwind semi-submersible floating platform configuration for a single horizontal axis wind turbine using data from two experimental testing investigations. A Smoothed Particle Hydrodynamics solver is employed to estimate fluid induced loads, whereas the mooring connections are handled via an external library. The first validation setup is based on the DeepCwind offshore wind semi-submersible concept moored with a system of taut-lines and tested for free-decay surge and heave motion (OC6-Phase Ia). The damping evaluation yields a fair estimation of the heave damping behavior, whereas much more dissipation is experienced for the surge. The second validation features a full hydrodynamic characterization of the frequency-related load patterns induced by three different sea-state representations (mono-, bi-chromatic, and irregular waves) (OC6-Phase Ib). The model accurately matches the hydrodynamic load estimation for the whole spectrum of investigated wave components, perfectly capturing the non-linear behavior shown by the considered wave patterns. This work concludes with a systematic study on the motion response, mooring tension, pressure and vorticity, suggesting that: the wave steepness criterion alone cannot identify the most restrictive load case; waves with spectral characteristics close to the heave resonance period lead to higher tensions in the mooring systems, whereas the maximum fluid-induced loads on the hull are decoupled from displacement peaks, showing an average reduction of 30% with respect to the maxima; very steep waves maximize the likelihood of wave overtopping and slamming loads, resulting in locally induced overpressure on the free-board of up to 100% higher than expected for similar wave heights with milder profiles. The input data for these last tests is released for the sake of reproduction. Agencia Estatal de Investigación | Ref. PID2020-113245RB-I00 Agencia Estatal de Investigación | Ref. TED2021-129479A-I00 Agencia Estatal de Investigación | Ref. PID2020-115030RJ-I00 Agencia Estatal de Investigación | Ref. RYC2020-030197 Xunta de Galicia | Ref. ED431C 2021/44 Xunta de Galicia | Ref. ED481A-2021/337 Universidade de Vigo/CISUG
Archivio della Ricer... arrow_drop_down Archivio della Ricerca - Università di SalernoArticle . 2023License: CC BY NC NDData sources: Archivio della Ricerca - Università di SalernoUniversitat Politècnica de Catalunya, BarcelonaTech: UPCommons - Global access to UPC knowledgeArticle . 2023License: CC BYData sources: Bielefeld Academic Search Engine (BASE)Recolector de Ciencia Abierta, RECOLECTAArticle . 2023License: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTARecolector de Ciencia Abierta, RECOLECTAArticle . 2023 . Peer-reviewedLicense: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTAUPCommons. Portal del coneixement obert de la UPCArticle . 2023 . Peer-reviewedLicense: CC BYData sources: UPCommons. Portal del coneixement obert de la UPCPublikationer från Uppsala UniversitetArticle . 2023 . Peer-reviewedData sources: Publikationer från Uppsala UniversitetDigitala Vetenskapliga Arkivet - Academic Archive On-lineArticle . 2023 . Peer-reviewedQueen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2023.103757&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen hybrid 23 citations 23 popularity Average influence Average impulse Top 10% Powered by BIP!
visibility 38visibility views 38 download downloads 76 Powered bymore_vert Archivio della Ricer... arrow_drop_down Archivio della Ricerca - Università di SalernoArticle . 2023License: CC BY NC NDData sources: Archivio della Ricerca - Università di SalernoUniversitat Politècnica de Catalunya, BarcelonaTech: UPCommons - Global access to UPC knowledgeArticle . 2023License: CC BYData sources: Bielefeld Academic Search Engine (BASE)Recolector de Ciencia Abierta, RECOLECTAArticle . 2023License: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTARecolector de Ciencia Abierta, RECOLECTAArticle . 2023 . Peer-reviewedLicense: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTAUPCommons. Portal del coneixement obert de la UPCArticle . 2023 . Peer-reviewedLicense: CC BYData sources: UPCommons. Portal del coneixement obert de la UPCPublikationer från Uppsala UniversitetArticle . 2023 . Peer-reviewedData sources: Publikationer från Uppsala UniversitetDigitala Vetenskapliga Arkivet - Academic Archive On-lineArticle . 2023 . Peer-reviewedQueen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2023.103757&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2013 United KingdomPublisher:Wiley Authors: Jiang, Zhiyu; Karimirad, Madjid; Moan, Torgeir;doi: 10.1002/we.1639
ABSTRACTThis study focuses on the dynamic responses of land‐based and floating wind turbines under blade pitch system fault and emergency shutdown conditions. The NREL 5 MW turbine is studied. A hydraulic pitch system is considered, and the faults under study are events with a seized blade or a blade running out of control. Emergency shutdown is defined as a fast pitch‐to‐feather maneuver of the blades. Load cases with power production and grid fault with ensuing shutdown are also analysed for comparison. The fault scenarios and the blades' fast pitching activity are simulated using HAWC2 through external Dynamic Link Libraries. On the basis of the time‐domain simulations, the response characteristics of the land‐based and the floating turbines in the four design load cases are compared. The load effects from the fault conditions are compared with the operational cases. Strong system dynamics and resonant responses, such as the tower elastic mode and the yaw resonant response, are elicited during shutdown. If the pitch system has a fault and one blade is hindered from normal pitching, the uneven load distribution of the blades leads to large structural and motion responses. For both turbines, the response maxima vary cyclically with the instantaneous azimuth when the blades start pitching to feather. For the floating wind turbine, the interaction of waves and wind also affects the results. The effect of the pitch rate during shutdown is analysed. The responses of the land‐based turbine in grid loss and shutdown conditions are proportional to the pitch rate, whereas decreased sensitivity is found in the cases with pitch system faults. For the floating turbine, the effect of the pitch rate is small, and reduced pitch and yaw motion extremes are observed as the pitch rate increases. Copyright © 2013 John Wiley & Sons, Ltd.
Wind Energy arrow_drop_down Wind EnergyArticle . 2013 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2014Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1002/we.1639&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 80 citations 80 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Wind Energy arrow_drop_down Wind EnergyArticle . 2013 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2014Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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description Publicationkeyboard_double_arrow_right Article 2023 United KingdomPublisher:Elsevier BV Hossein Yazdi; Hamid Reza Ghafari; Hassan Ghassemi; Guanghua He; Madjid Karimirad;Integrating a floating offshore wind turbine (FOWT) and an array of wave energy converters (WECs) can be suggested as a proper new hybrid concept with the aim of more energy harvesting and lower total energy cost. This paper proposes the new composition of a floating braceless semi-submersible platform and an array of Salter's duck (SD) WECs. First, a comparison of the numerical results and experimental data of the hydrodynamics response of FOWT and the single SD WEC response are presented and discussed. Then, the performance of three-hybrid FOWT-Multi-Salter's Duck (FOWT-MSD) systems with 12SD, 15SD, and 18SD WECs has been investigated under different wave periods and wave heights. In the wave period of 6–9 s, 12SD absorbs more power than 15SD and 18SD. From T = 9–11 s, all three systems have the same absorbed power. For wave periods above 12 s, 15SD and 18SD have higher absorbed power than 12SD. No clear trend was observed for wave periods below 6 s. The effect of wave direction shows that at lower wave heights, maximum absorber power belongs to FOWT-12SD under zero wave direction. In contrast, increasing wave heights leads to a smaller difference between the three-hybrid systems at different wave directions.
Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2023.127930&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen 29 citations 29 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)Queen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2023.127930&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012Publisher:Elsevier BV Authors: Torgeir Moan; Madjid Karimirad;AbstractThe feasibility of the application of a spar-type wind turbine at a moderate water depth is studied in this paper. In the oil and gas industries, spar-type offshore platforms are widely applied in deep water. The same idea is used in offshore wind technology to present the Hywind concept based on a catenary moored spar in deep water. The draft of the spar limits the application of spar-type wind turbines in shallow water. However, it is possible to design spar-type wind turbines for moderate water depths. The present article studies the feasibility and performance of such a design. A spar-type wind turbine at a moderate water depth called “ShortSpar” is introduced in the present article. A catenary moored spar-type support structure is applied as a base for the 5-MW NREL land-based turbine. The power performance, structural integrity and dynamic responses of a 5-MW catenary moored spar-type wind turbine in deep water (DeepSpar) have previously been studied. In the present article, the responses of the spar-type wind turbines, ShortSpar and DeepSpar, are compared. The HAWC2 code is used to carry out the coupled aero-hydro-servo-elastic analyses. Different environmental conditions are used to compare the responses. A dynamic link library (DLL) is used to feed the mooring forces at each time step into the HAWC2 code. The force-displacement relationships are obtained from the Simo-Riflex code. The comparison of the responses of ShortSpar and DeepSpar in different load cases indicates the feasibility of implementation of spar-type wind turbine in moderate water depths. The results show that the spar-type wind turbine at a moderate water depth exhibits good performance, and its responses are reasonable compared with those associated with a spar-type wind turbine in deep water. The total mass (the structural mass plus the ballast) of ShortSpar is 35% less than the mass of DeepSpar, while the statistical characteristics of the generated power are almost the same for both spars. This mass reduction for ShortSpar helps to achieve a more cost-effective solution for floating wind turbines at a moderate water depth.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2012.06.117&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 25 citations 25 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2012.06.117&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012Publisher:American Society of Civil Engineers (ASCE) Authors: Madjid Karimirad; Torgeir Moan;This paper addresses coupled wave and wind-induced motions of spar-type 5-MW wind turbines in harsh and operational environmental conditions. Global dynamic motion responses have been analyzed by aero-hydro-servo-elastic time-domain simulations. The aerodynamics is based on an advanced blade element momentum theory. Panel method and Morison formula accounting for the instantaneous position of the structure are applied for hydrodynamics. Hydrodynamic drag and considering geometrical updating introduce nonlinearities. Hydrodynamic nonlinearities were found to cause excitation of the natural frequencies in the low frequency range more than in the wave frequency range. Extrapolation methods are applied to estimate the maximum responses. A previous study showed that the uncertainty of such an extrapolation for the present concept is less than 2%. In this study it is found that the mean values of the dynamic responses are primarily wind induced and the standard deviations of the responses are primarily wave ind...
Journal of Waterway ... arrow_drop_down Journal of Waterway Port Coastal and Ocean EngineeringArticle . 2012 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1061/(asce)ww.1943-5460.0000087&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu117 citations 117 popularity Top 1% influence Top 1% impulse Top 1% Powered by BIP!
more_vert Journal of Waterway ... arrow_drop_down Journal of Waterway Port Coastal and Ocean EngineeringArticle . 2012 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1061/(asce)ww.1943-5460.0000087&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 United KingdomPublisher:Wiley Authors: Karimirad, Madjid; Moan, Torgeir;doi: 10.1002/we.1537
ABSTRACTThis paper presents a stochastic dynamic response analysis of a tension leg spar‐type wind turbine subjected to wind and wave actions. The dynamic motions, structural responses, power production and tension leg responses are analyzed. The model is implemented using the HAWC2 code. Several issues such as negative damping, rotor configuration (upwind or downwind rotor) and tower shadow effects are discussed to study the power performance and structural integrity of the system. The operational and survival load cases considering the stochastic wave and wind loading are analyzed to investigate the functionality of the tension leg spar‐type wind turbine. Amelioration of the negative damping applied for this concept reduces the structural dynamic responses, which are important for fatigue life. It is found that the responses induced by wave and wind actions at the wave frequencies are not affected much by the aerodynamic excitation or damping forces. Because of the nonlinear effects of the tension leg, all of the motion responses are strongly coupled. The global responses of upwind and downwind versions of the turbine are found to be close because the tower shadow has a limited effect on the global responses. However, the structural dynamic responses of the blades are more affected by the tower shadow. In this study, the extrapolation methods are applied to efficiently estimate the maximum responses. The maximum response is found to occur in the survival cases as a result of the wave actions and the increased aerodynamic drag forces on the tower. The results show that the maximum responses corresponding to the up‐crossing rate of 0.0001 (corresponding to the maximum response within a 3 hour period) can be expressed by the mean plus 3 to 5 standard deviations. Copyright © 2012 John Wiley & Sons, Ltd.
Wind Energy arrow_drop_down Wind EnergyArticle . 2012 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2013Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1002/we.1537&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 26 citations 26 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Wind Energy arrow_drop_down Wind EnergyArticle . 2012 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2013Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1002/we.1537&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2015 United KingdomPublisher:Elsevier BV Authors: Karimirad, Madjid; Michailides, Constantine;AbstractThe development of cost effective floating type offshore wind turbines has been desired in deep sea areas. Semisubmersible platform can be considered as a very efficient design configuration among the different type proposed floating platforms. In the present paper, a preliminary assessment of the dynamic behavior of a 5-MW braceless semisubmersible offshore wind turbine with three columns and two fully submerged pontoons is presented for selected environmental operational conditions that correspond to a deep water offshore site with depth 200 m. Hydro-aero-servo-elastic time domain analysis is performed with the use of the coupled analysis tool Simo-Riflex-AeroDyn in order to calculate the dynamic behavior and response of the offshore floating wind turbine. Statistical values and spectra of time histories of response quantities are presented. The results demonstrate the feasibility of the presented deep sea floating wind turbine concept.
Energy Procedia arrow_drop_down Queen's University Belfast Research PortalArticle . 2015Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2015.11.402&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 13 citations 13 popularity Top 10% influence Average impulse Average Powered by BIP!
more_vert Energy Procedia arrow_drop_down Queen's University Belfast Research PortalArticle . 2015Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.egypro.2015.11.402&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2024 United KingdomPublisher:Elsevier BV Jie Fu; Xu Han; Wei Shi; Madjid Karimirad; Xin Li;Physical model-scale testing could assist in identifying important coupling effects and validating numerical simulations. However, the requirement regarding the dynamic similarity for the offshore wind turbine model is difficult to meet due to the scaling effects. To address this challenge, a testing method is proposed, using a linear actuator to reproduce the required aerodynamic force for the real-time hybrid model test. The magnitudes of the applied force were simulated using a numerical substructure developed based on the aerodynamic coupling analysis. This paper designed the physical substructure of offshore wind turbines, selected the "Hardware in the Loop" method, and conducted relevant experiments in a wave tank. The turbulent wind and pitch control were reproduced during the testing process. The experimental data and simulation results were compared and analyzed. The maximum error of the average values of different physical quantities (Rotor thrust force, Tower top displacement) measured was 5.51 %, while the maximum error in the standard values was −10.59 %. The data indicate good consistency between the experimental and simulation results. From the analysis of power spectral density (PSD) results of different physical quantities, it was found that turbulent wind provides significant excitation and energy in the frequency range below wave excitation. The frequency of turbulent wind loads hides the low-frequency second-order wave forces, indicating the necessity of reproducing turbulent winds in experiments. The real-time hybrid model test method can accurately reproduce the turbulent wind load, achieve the combined action of random wind and waves, and improve the model testing level of existing monopile offshore wind turbines.
Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104304&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!
more_vert Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104304&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2024 United KingdomPublisher:Elsevier BV Wei Shi; Jie Fu; Zhengru Ren; Madjid Karimirad; Huimeng Zhou; Xin Li;The real-time hybrid model (RTHM) test is adept at addressing the scale contradiction, the lack of fidelity in wind modelling in hydrodynamic testing facilities and spatial constraints inherent in conventional monopile-type offshore wind turbine (OWT) model testing methods, thus emerging as an effective avenue for conducting physical model tests of Monopile-type OWTs. This method entails the reproduction of aerodynamic loads or platform motions using loading device or vibration tables. Time delays in the physical attributes of the loading device and signal transmission processes within the system can result in error accumulation, with the potential to impact overall system stability. Moreover, time delay compensation algorithms for hybrid model test systems with force control loading can easily generate excessive noise, leading to system divergence. As a result, time delay has emerged as a technical challenge in the RTHM test. To address this issue, this paper has developed second-order and third-order polynomial extrapolation algorithms, alongside an adaptive compensation algorithm. The adaptive compensation algorithm employs the least squares method to identify parameters of the loading system, enabling it to address variations in the time delay of the experimental system caused by the nonlinearity of the loading system and changes in the physical properties of the model. The feasibility and effects of time delay compensation for various algorithms are validated through numerical simulation. Results indicate that the adaptive compensation algorithm surpasses second and third-order polynomial extrapolation compensation algorithms in terms of accuracy and compensation effectiveness. To validate the applicability of the adaptive compensation algorithm, a RTHM test was conducted. Across rotor thrust force (RotThrust) and tower top displacement, there was an average reduction of approximately 5% and 9% in the maximum and minimum synchronization errors, respectively. This highlights the efficacy of the delay compensation algorithm in practical applications, notably diminishing time delay errors within the experimental system. The adaptive compensation algorithm continuously adjusts and updates parameters, enhancing the adaptability of the compensation process to time-varying systems.
Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104234&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!
more_vert Queen's University R... arrow_drop_down Queen's University Belfast Research PortalArticle . 2024Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2024.104234&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal , Other literature type 2020 United KingdomPublisher:MDPI AG Authors: Mohsen Sobhaniasl; Francesco Petrini; Madjid Karimirad; Franco Bontempi;doi: 10.3390/en13123096
In this paper, a procedure is proposed to determine the fatigue life of the electrical cable connected to a 5 MW floating offshore wind turbine, supported by a spar-buoy at a water depth of 320 m, by using a numerical approach that takes into account site-specific wave and wind characteristics. The effect of the intensity and the simultaneous actions of waves and wind are investigated and the outcomes for specific cable configurations are shown. Finally, the fatigue life of the cable is evaluated. All analyses have been carried out using the Ansys AQWA computational code, which is a commercial code for the numerical investigation of the dynamic response of floating and fixed marine structures under the combined action of wind, waves and current. Furthermore, this paper applies the FAST NREL numerical code for comparison with the ANSYS AQWA results.
Energies arrow_drop_down EnergiesOther literature type . 2020License: CC BYFull-Text: http://www.mdpi.com/1996-1073/13/12/3096/pdfData sources: Multidisciplinary Digital Publishing InstituteQueen's University Belfast Research PortalArticle . 2020Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.3390/en13123096&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 25 citations 25 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Energies arrow_drop_down EnergiesOther literature type . 2020License: CC BYFull-Text: http://www.mdpi.com/1996-1073/13/12/3096/pdfData sources: Multidisciplinary Digital Publishing InstituteQueen's University Belfast Research PortalArticle . 2020Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2023 United Kingdom, Italy, Sweden, SpainPublisher:Elsevier BV Bonaventura Tagliafierro; Madjid Karimirad; Corrado Altomare; Malin Göteman; Iván Martínez-Estévez; Salvatore Capasso; José M. Domínguez; Giacomo Viccione; Moncho Gómez-Gesteira; Alejandro J.C. Crespo;handle: 2117/403843 , 11386/4845651 , 11093/5275
In this work, we propose numerical validations of the DeepCwind semi-submersible floating platform configuration for a single horizontal axis wind turbine using data from two experimental testing investigations. A Smoothed Particle Hydrodynamics solver is employed to estimate fluid induced loads, whereas the mooring connections are handled via an external library. The first validation setup is based on the DeepCwind offshore wind semi-submersible concept moored with a system of taut-lines and tested for free-decay surge and heave motion (OC6-Phase Ia). The damping evaluation yields a fair estimation of the heave damping behavior, whereas much more dissipation is experienced for the surge. The second validation features a full hydrodynamic characterization of the frequency-related load patterns induced by three different sea-state representations (mono-, bi-chromatic, and irregular waves) (OC6-Phase Ib). The model accurately matches the hydrodynamic load estimation for the whole spectrum of investigated wave components, perfectly capturing the non-linear behavior shown by the considered wave patterns. This work concludes with a systematic study on the motion response, mooring tension, pressure and vorticity, suggesting that: the wave steepness criterion alone cannot identify the most restrictive load case; waves with spectral characteristics close to the heave resonance period lead to higher tensions in the mooring systems, whereas the maximum fluid-induced loads on the hull are decoupled from displacement peaks, showing an average reduction of 30% with respect to the maxima; very steep waves maximize the likelihood of wave overtopping and slamming loads, resulting in locally induced overpressure on the free-board of up to 100% higher than expected for similar wave heights with milder profiles. The input data for these last tests is released for the sake of reproduction. Agencia Estatal de Investigación | Ref. PID2020-113245RB-I00 Agencia Estatal de Investigación | Ref. TED2021-129479A-I00 Agencia Estatal de Investigación | Ref. PID2020-115030RJ-I00 Agencia Estatal de Investigación | Ref. RYC2020-030197 Xunta de Galicia | Ref. ED431C 2021/44 Xunta de Galicia | Ref. ED481A-2021/337 Universidade de Vigo/CISUG
Archivio della Ricer... arrow_drop_down Archivio della Ricerca - Università di SalernoArticle . 2023License: CC BY NC NDData sources: Archivio della Ricerca - Università di SalernoUniversitat Politècnica de Catalunya, BarcelonaTech: UPCommons - Global access to UPC knowledgeArticle . 2023License: CC BYData sources: Bielefeld Academic Search Engine (BASE)Recolector de Ciencia Abierta, RECOLECTAArticle . 2023License: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTARecolector de Ciencia Abierta, RECOLECTAArticle . 2023 . Peer-reviewedLicense: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTAUPCommons. Portal del coneixement obert de la UPCArticle . 2023 . Peer-reviewedLicense: CC BYData sources: UPCommons. Portal del coneixement obert de la UPCPublikationer från Uppsala UniversitetArticle . 2023 . Peer-reviewedData sources: Publikationer från Uppsala UniversitetDigitala Vetenskapliga Arkivet - Academic Archive On-lineArticle . 2023 . Peer-reviewedQueen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2023.103757&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen hybrid 23 citations 23 popularity Average influence Average impulse Top 10% Powered by BIP!
visibility 38visibility views 38 download downloads 76 Powered bymore_vert Archivio della Ricer... arrow_drop_down Archivio della Ricerca - Università di SalernoArticle . 2023License: CC BY NC NDData sources: Archivio della Ricerca - Università di SalernoUniversitat Politècnica de Catalunya, BarcelonaTech: UPCommons - Global access to UPC knowledgeArticle . 2023License: CC BYData sources: Bielefeld Academic Search Engine (BASE)Recolector de Ciencia Abierta, RECOLECTAArticle . 2023License: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTARecolector de Ciencia Abierta, RECOLECTAArticle . 2023 . Peer-reviewedLicense: CC BYData sources: Recolector de Ciencia Abierta, RECOLECTAUPCommons. Portal del coneixement obert de la UPCArticle . 2023 . Peer-reviewedLicense: CC BYData sources: UPCommons. Portal del coneixement obert de la UPCPublikationer från Uppsala UniversitetArticle . 2023 . Peer-reviewedData sources: Publikationer från Uppsala UniversitetDigitala Vetenskapliga Arkivet - Academic Archive On-lineArticle . 2023 . Peer-reviewedQueen's University Belfast Research PortalArticle . 2023Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apor.2023.103757&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2013 United KingdomPublisher:Wiley Authors: Jiang, Zhiyu; Karimirad, Madjid; Moan, Torgeir;doi: 10.1002/we.1639
ABSTRACTThis study focuses on the dynamic responses of land‐based and floating wind turbines under blade pitch system fault and emergency shutdown conditions. The NREL 5 MW turbine is studied. A hydraulic pitch system is considered, and the faults under study are events with a seized blade or a blade running out of control. Emergency shutdown is defined as a fast pitch‐to‐feather maneuver of the blades. Load cases with power production and grid fault with ensuing shutdown are also analysed for comparison. The fault scenarios and the blades' fast pitching activity are simulated using HAWC2 through external Dynamic Link Libraries. On the basis of the time‐domain simulations, the response characteristics of the land‐based and the floating turbines in the four design load cases are compared. The load effects from the fault conditions are compared with the operational cases. Strong system dynamics and resonant responses, such as the tower elastic mode and the yaw resonant response, are elicited during shutdown. If the pitch system has a fault and one blade is hindered from normal pitching, the uneven load distribution of the blades leads to large structural and motion responses. For both turbines, the response maxima vary cyclically with the instantaneous azimuth when the blades start pitching to feather. For the floating wind turbine, the interaction of waves and wind also affects the results. The effect of the pitch rate during shutdown is analysed. The responses of the land‐based turbine in grid loss and shutdown conditions are proportional to the pitch rate, whereas decreased sensitivity is found in the cases with pitch system faults. For the floating turbine, the effect of the pitch rate is small, and reduced pitch and yaw motion extremes are observed as the pitch rate increases. Copyright © 2013 John Wiley & Sons, Ltd.
Wind Energy arrow_drop_down Wind EnergyArticle . 2013 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2014Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1002/we.1639&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 80 citations 80 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert Wind Energy arrow_drop_down Wind EnergyArticle . 2013 . Peer-reviewedLicense: Wiley Online Library User AgreementData sources: CrossrefQueen's University Belfast Research PortalArticle . 2014Data sources: Bielefeld Academic Search Engine (BASE)add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1002/we.1639&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu