Reducing drag forces and minimizing the rear wake region are the main goals of evaluating exterior aerodynamic performance in automobiles. Various literature and experiments shows that the overall fuel computations of the road vehicle improves significantly with the reduction in aerodynamic drag force. In the road vehicle major components of the drag is due the imbalance in pressure between front and rear of the vehicle. At high vehicle speed, aerodynamic drag is responsible for approximately 30 to 40% of the energy consumption of the vehicle.
In the recent year, cost of high-performance computing (HPC) has reduced significantly, which helped computational fluid dynamics (CFD) is an affordable tool to the automotive industry for evaluating aerodynamic performance of the vehicle during developing phase. The vehicles aerodynamic performance is greatly impacted by the dynamic environmental conditions it encounters in the real world. Such environmental conditions are difficult to replicate in a traditional wind tunnel test. To mitigate these testing conditions advanced wind tunnel testing has taken into account the use of boundary layer suction devices rotating wheels and moving ground.
This study aims to characterize a passenger vehicle's rear wake structure by measuring pressure coefficients through an array of pressure taps located on the rear surface. To study the wake dynamics based on the pressure data collected, a tomographic reconstruction method is used. Computational fluid dynamics (CFD) demonstrates strong potential as a cost-effective and reliable method for replicating complex aerodynamic phenomena under realistic operating conditions within a virtual environment. This paper concludes with a comparative analysis between CFD simulation results and wind tunnel measurements for an automotive vehicle, emphasizing key aerodynamic parameters such as drag force, surface pressure coefficients at critical locations, and the characterization of rear wake structures.