CFD analysis and aerodynamic effects of add-on devices on an audi TT vehicle model

Abstract

Environmental issues and increased fuel prices are driving automotive manufacturers to develop more fuel-efficient vehicles with lower emissions. Due to the limitations of conventional wind tunnel experiments and rapid developments in computer hardware, considerable efforts have been invested to study vehicle aerodynamics computationally. The ANSYS computer software package is employed, and 3D computer model cars are designed by the SolidWorks software. The Fluent subpackage is used to evaluate the aerodynamic behavior. This paper concentrates on the prediction of lift and drag for the car body using Computational Fluid Dynamics (CFD) on three different models of vehicles for simulation without any devices, with a rear wing or spoiler, and with vortex generators. Turbulence modeling was done with the realizable k-ε model using standard wall functions. The computational results for the three models are provided. The drag and lift coefficients that we have found are 0.4142 and 0.4338, respectively; compared with model 2, they are 0.4585 and 0.0387, and for model 3, they are 0.3971 and 0.3858, respectively. Model 2 has shown that the aerodynamic drag has increased from 0.4142 to 0.4585, which is a 10.69% drag increment. In addition, it showed an increase in negative lift by reducing the lift coefficient from 0.4338 to -0.0387, which is a 91.07% lift reduction by comparing with model 1. Similarly, model 3 has shown that the aerodynamic drag is reduced from 0.4142 to 0.3971, which is a 4.12% drag reduction, and it also showed an increase in negative lift by decreasing the lift coefficient from 0.4338 to 0.3858, which is a 11.06% lift reduction.