• Energy Research

Abstract This paper presents results of investigations focused on a pressure wave exchanger demonstrator, constructed at the Aerodynamics Division at Warsaw University of Technology. Main flow features of the device were analyzed and experimental data was collected in order to perform validation of CFD calculations. Three different turbulence models (Standard-k-ω, SST-k-ω and SST-SAS) were used in simulations and tested in unsteady conditions. Data in form of: velocity field, shape and position of the contact surface between the driving and the driven medium served to perform comparison between PIV measurements and numerical calculations, which revealed that the best correlation between experiments and numerical data was obtained with SST-SAS turbulence model.

This paper discusses the capabilities of side spoilers to improve the aerodynamic properties of a sports car exposed to a non-zero yaw angle flow. In such conditions, the aerodynamic drag and lift both increase with the introduction of a side force and a yawing moment, which contribute to the decrease of the car’s handling properties and force the car to change its driving path. Elements mounted on the side of the car make it possible to obtain an asymmetric aerodynamic load distribution and generate additional forces that can be used to counter these effects. The performance of the side spoilers was analyzed at yaw angles ranging from 0° to 15° using the results of numerical calculations. It was established that the side spoilers made it possible to generate at low yaw angles aerodynamic forces that exceeded those caused by a crosswind.

Abstract This paper presents an analysis of several different aerodynamic setups that can be utilized to improve the braking performance of a sports car. The coefficients of aerodynamic forces and the flow properties of a targa top car body were investigated with the use of wind tunnel data as well as the results of CFD calculations. The influence of a car body's rear wing utilized as an air brake was presented at a low angle of attack and at a high angle of attack. The balance of the car body was investigated and it was shown how the load on the front and rear axles of the car can be affected by an air brake placed in different locations. An alternative method for the increase of the download force was also studied which included the use of small movable elements that are easy to hide within the silhouette of the car body. Due to the increase of the car's drag coefficient by 0.58 and the decrease of the lift coefficient by 1.1, the braking distance can be reduced up to 31%, depending on the vehicle's speed and driving conditions, which proves that active aerodynamics utilized in braking mode can contribute to the improvement of driving safety.

This study was prepared to demonstrate how the aerodynamics of a sports car can be enhanced, emphasizing aerodynamic improvements, and utilizing small movable elements. All the presented results were obtained using the numerical simulations performed in ANSYS Fluent in steady-state conditions. It was investigated how the performance of a car equipped with the splitter and the rear wing could be improved. The benefits of a top-mounted wing configuration were presented compared to a bottom-mounted setup. A change to the top-mounting configuration enabled undisturbed flow around the suction side of the wing and a more favorable placement of the wing to the car body. In the given case, an 80% increase of downforce was achieved in the performance mode of the car setup and a 16% increase of drag in the air braking mode. A method of the front splitter active steering was presented, which enabled a change of the generated downforce using only a small element that enabled an instant change of 30% without the necessity of moving the whole splitter plate. The described modifications of the sports car not only improved its aerodynamic properties but also enabled the means to accommodate it with an active aerodynamic system that would allow a quick adaptation to the current driving conditions.

The aim of this study was to extend the safety limits of fast moving cars by the application, in a controlled way, of aerodynamic forces which increase as the square of a car’s velocity and, if left uncontrolled, dramatically reduce car safety. This paper presents the methods, assumptions, and results of numerical and experimental investigations by modeling and simulation of the aerodynamic characteristics and dynamics of a small sports car equipped with movable aerodynamic elements operated by an electronic subsystem for data acquisition and aerodynamics active automatic control.