Wheel and tire rotation play a significant role in the aerodynamics of automotive shapes. Wheel, tire and wheel house account for almost 30% of the total aerodynamic drag, and the wheel rotation significantly changes the pressure inside the wheel house and affects the lift significantly. Wheel rotation creates pumping of flow through the wheel which significantly influences the wheel house pressures. Simulating wheel rotation using traditional methods such as the rotating wall boundary condition and the Multiple Reference Frame (MRF) method for simulating rotation of fluid region around the wheels have yielded satisfactory results, but to accurately capture the flow physics and resulting integral quantities such as aerodynamic drag and lift, simulation of wheels using true rotating geometry was deemed essential. With true rotating geometry (sliding mesh), aerodynamic prediction of integral quantities shows excellent agreement with the experimental values where largest drag error was less than 2% and for most of the cases less than 1%. The errors in front and rear lift coefficients are less than 10 counts (0.010) for any cases considered and for most cases it was less than 5 counts (0.005). Predictions with MRF boundary condition showed accuracy levels better than those of rotating wall boundary conditions for front and rear lift, but for drag prediction both rotating wall and MRF simulations deviate by about 5%. Lift balance predictions with sliding mesh boundary conditions match the experimental magnitude and trends very well and are superior to the predictions by the other two methodologies. The purpose of this paper is to evaluate the importance of wheel rotation on the aerodynamic performance metrics of vehicles. From the results presented here, it can be concluded that approximate methods such as rotating wall boundary conditions and MRF conditions can yield acceptable results for trend predictions but show larger discrepancies in the prediction of absolute values for lift coefficients, which is crucial for the high speed performance of the vehicle. Modelling actual wheel rotation is important in order to obtain accurate prediction of all the aerodynamic coefficients and the pressure levels in the under body and wheel house areas, which have a significant effect on the flow around the wheels.
Impact of wheel rotation on aerodynamic drag and lift
Einfluß der Raddrehung auf den aerodynamischen Widerstand und Auftrieb
2012
23 Seiten, 12 Bilder, 42 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
Impact of wheel rotation on aerodynamic drag and lift
Kraftfahrwesen | 2012
|Aerodynamic devices for enhancing lift and reducing drag
Europäisches Patentamt | 2021
|AERODYNAMIC DEVICES FOR ENHANCING LIFT AND REDUCING DRAG
Europäisches Patentamt | 2018
|Aerodynamic Devices for Enhancing Lift and Reducing Drag
Europäisches Patentamt | 2018
|