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description Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 ItalyPublisher:MDPI AG Authors: Matteo Gregori; Francesco Salvatore; Roberto Camussi;This paper presents a novel theoretical and computational methodology for the generation of an onset turbulent field with prescribed properties in the numerical simulation of an arbitrary viscous flow. The methodology is based on the definition of a suitable distribution of volume force terms in the right–hand side of the Navier–Stokes equations. The distribution is represented by harmonic functions that are randomly variable in time and space. The intensity of the distribution is controlled by a simple PID strategy in order to obtain that the generated turbulent flow matches a prescribed turbulence intensity. A further condition is that a homogeneous isotropic flow is es- tablished downstream of the region where volume force terms are imposed. Although it is general, the proposed methodology is primarily intended for the computational modelling of hydrokinetic turbines in turbulent flows representative of tidal or riverine installations. A first numerical applica- tion is presented by considering the injection of homogeneous and isotropic turbulence with 16% intensity into a uniform unbounded flow. The analysis of statistical properties as auto-correlation, power spectral density, probability density functions, demonstrates that the generated flow tends to achieve satisfactory levels of stationarity and isotropy, whereas the simple control strategy used determines overestimated turbulent intensity levels.
Journal of Marine Sc... arrow_drop_down Journal of Marine Science and EngineeringOther literature type . 2022License: CC BYFull-Text: http://www.mdpi.com/2077-1312/10/10/1332/pdfData sources: Multidisciplinary Digital Publishing Institutehttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefJournal of Marine Science and EngineeringArticle . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefhttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2022Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.20944/preprints202208.0211.v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!
more_vert Journal of Marine Sc... arrow_drop_down Journal of Marine Science and EngineeringOther literature type . 2022License: CC BYFull-Text: http://www.mdpi.com/2077-1312/10/10/1332/pdfData sources: Multidisciplinary Digital Publishing Institutehttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefJournal of Marine Science and EngineeringArticle . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefhttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2022Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.20944/preprints202208.0211.v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 ItalyPublisher:Cambridge University Press (CUP) Authors: Felli M; Camussi R; Di Felice F;doi: 10.1017/jfm.2011.150
handle: 20.500.14243/217958 , 11590/118771
In the present study the mechanisms of evolution of propeller tip and hub vortices in the transitional region and the far field are investigated experimentally. The experiments involved detailed time-resolved visualizations and velocimetry measurements and were aimed at examining the effect of the spiral-to-spiral distance on the mechanisms of wake evolution and instability transition. In this regard, three propellers having the same blade geometry but different number of blades were considered. The study outlined dependence of the wake instability on the spiral-to-spiral distance and, in particular, a streamwise displacement of the transition region at the increasing inter-spiral distance. Furthermore, a multi-step grouping mechanism among tip vortices was highlighted and discussed. It is shown that such a phenomenon is driven by the mutual inductance between adjacent spirals whose characteristics change by changing the number of blades.
Journal of Fluid Mec... arrow_drop_down Journal of Fluid MechanicsArticle . 2011 . Peer-reviewedLicense: Cambridge Core User AgreementData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2011Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.1017/jfm.2011.150&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu310 citations 310 popularity Top 0.1% influence Top 1% impulse Top 1% Powered by BIP!
more_vert Journal of Fluid Mec... arrow_drop_down Journal of Fluid MechanicsArticle . 2011 . Peer-reviewedLicense: Cambridge Core User AgreementData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2011Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.1017/jfm.2011.150&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu
description Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 ItalyPublisher:MDPI AG Authors: Matteo Gregori; Francesco Salvatore; Roberto Camussi;This paper presents a novel theoretical and computational methodology for the generation of an onset turbulent field with prescribed properties in the numerical simulation of an arbitrary viscous flow. The methodology is based on the definition of a suitable distribution of volume force terms in the right–hand side of the Navier–Stokes equations. The distribution is represented by harmonic functions that are randomly variable in time and space. The intensity of the distribution is controlled by a simple PID strategy in order to obtain that the generated turbulent flow matches a prescribed turbulence intensity. A further condition is that a homogeneous isotropic flow is es- tablished downstream of the region where volume force terms are imposed. Although it is general, the proposed methodology is primarily intended for the computational modelling of hydrokinetic turbines in turbulent flows representative of tidal or riverine installations. A first numerical applica- tion is presented by considering the injection of homogeneous and isotropic turbulence with 16% intensity into a uniform unbounded flow. The analysis of statistical properties as auto-correlation, power spectral density, probability density functions, demonstrates that the generated flow tends to achieve satisfactory levels of stationarity and isotropy, whereas the simple control strategy used determines overestimated turbulent intensity levels.
Journal of Marine Sc... arrow_drop_down Journal of Marine Science and EngineeringOther literature type . 2022License: CC BYFull-Text: http://www.mdpi.com/2077-1312/10/10/1332/pdfData sources: Multidisciplinary Digital Publishing Institutehttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefJournal of Marine Science and EngineeringArticle . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefhttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2022Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.20944/preprints202208.0211.v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!
more_vert Journal of Marine Sc... arrow_drop_down Journal of Marine Science and EngineeringOther literature type . 2022License: CC BYFull-Text: http://www.mdpi.com/2077-1312/10/10/1332/pdfData sources: Multidisciplinary Digital Publishing Institutehttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefJournal of Marine Science and EngineeringArticle . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefhttps://doi.org/10.20944/prepr...Article . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2022Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.20944/preprints202208.0211.v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 ItalyPublisher:Cambridge University Press (CUP) Authors: Felli M; Camussi R; Di Felice F;doi: 10.1017/jfm.2011.150
handle: 20.500.14243/217958 , 11590/118771
In the present study the mechanisms of evolution of propeller tip and hub vortices in the transitional region and the far field are investigated experimentally. The experiments involved detailed time-resolved visualizations and velocimetry measurements and were aimed at examining the effect of the spiral-to-spiral distance on the mechanisms of wake evolution and instability transition. In this regard, three propellers having the same blade geometry but different number of blades were considered. The study outlined dependence of the wake instability on the spiral-to-spiral distance and, in particular, a streamwise displacement of the transition region at the increasing inter-spiral distance. Furthermore, a multi-step grouping mechanism among tip vortices was highlighted and discussed. It is shown that such a phenomenon is driven by the mutual inductance between adjacent spirals whose characteristics change by changing the number of blades.
Journal of Fluid Mec... arrow_drop_down Journal of Fluid MechanicsArticle . 2011 . Peer-reviewedLicense: Cambridge Core User AgreementData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2011Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.1017/jfm.2011.150&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu310 citations 310 popularity Top 0.1% influence Top 1% impulse Top 1% Powered by BIP!
more_vert Journal of Fluid Mec... arrow_drop_down Journal of Fluid MechanicsArticle . 2011 . Peer-reviewedLicense: Cambridge Core User AgreementData sources: CrossrefArchivio della Ricerca - Università degli Studi Roma TreArticle . 2011Data sources: Archivio della Ricerca - Università degli Studi Roma Treadd 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=10.1017/jfm.2011.150&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu