Computational Flow Prediction and Design Optimization of Vortex Generators for a Conventional Passenger Car

Abstract

Vehicle aerodynamics is a vital physics in the design of an automotive vehicle. The main purpose of the automotive aerodynamics is to reduce drag force, wind noise, minimizing noise emission and preventing the undesired lift forces to avoid aerodynamic instability at high speeds. The shape of the vehicle body is to be designed in such a way that drag force caused by the pressure and viscous effects is less. The present analysis focuses on the drag reduction technique used for a passenger car \ using vortex generator. The main purpose of using Vortex Generators (VGs) is to disturb the airflow running over the car body and hence to produce a swirl of air in-between the high energy and low energy streams. In this paper, different shapes of vortex generators are considered and numerically investigated using Computational Fluid Dynamics (CFD). The flow characteristics around the car body with and without vortex generators are predicted and compared. The drag forces obtained using CFD simulations are compared with various vortex generator configurations. The present analysis also investigates the combined effect of spoiler with vortex generators and the change in aerodynamic characteristics of the car body is presented. The flow interference over the spoiler due to the presence of vortex generators is predicted to compare the changes in negative lift produced during high speeds. From the CFD analysis it is observed that there is less co-efficient of drag in ramped type VGs in comparison with other VGs.