Numerical study of the effect of vortex generators arrangement on vehicle aerodynamic characteristics

Land vehicles are among the blunt body objects. When a vehicle moves forward, the movement of air around it produces a pressure gradient that varies along the body. This can lead to separation and appearance of a turbulent wake region in the rear of the vehicle. The present study numerically investigates the aerodynamic effects of vortex generators and their arrangement in different positions of 6 and 15 numbers, each with linear, rectangular and triangular arrangements on the back of a car model. Reynolds-Averaged Navier-Stokes (RANS) equations and turbulent models have been used to analyze the changes in drag and lift coefficients obtained from different arrangements of the vortex generators. The results show that the best case for reducing the drag force is related to 6 numbers of vortex generators with linear and triangular arrangement, which reduces the drag coefficient by 2% compared to the car model without vortex generators. In addition, the best case to improve the downforce; in order to increase the stability of the car, is the arrangement of 15 vortex generators with a rectangular alignment, which reduces the lift coefficient by 23.1% compared to the car model without the vortex generator. Also, with increasing the number of vortex generators from 6 to 15, the drag coefficients generally increase.