Authors : Harinaldi , Budiarso , Warjito , Engkos A. Kosasih, Rustan Tarakka and Sabar P. Simanungkalit
Abstract: Today research trend in car aerodynamics are carried out from the point of view of the durable development. Some car companies have the objective to develop control solution that enable to reduce the aerodynamic drag of vehicle. It provides the possibility to modify the flow separation to reduce the development of the swirling structures around the vehicle. In this study, a family van was modeled with a modified form of Ahmed’s body by changing the orientation of the flow from its original form (modified/reversed Ahmed body). This model was equipped with a suction on the rear side to comprehensively examine the pressure field modifications that occur. The investigation combined computational and experimental work. The computational simulation used k-epsilon Flow Turbulence Model. The reversed Ahmed body used in the investigation had slant angle (φ) 35° at the front part. In the computational work, meshing type was tetra/hybrid element with hex core type and the grid number was >1.7 million in order to ensure detail discretization and more accurate calculation results. The boundary condition was upstream velocity of 11.1 m sec-1. Mean free stream at far upstream region was assumed in a steady state condition and uniform. The suction velocity was set at 1 m sec-1. Meanwhile in the experimental work a reversed Ahmed model was tested in a controlled wind tunnel experiments. The main measurement was the aerodynamic drag force measurement at rear of the body of the model using load cell. The results showed that the application of a suction in the rear part of the van model gave the effect of reducing the wake and the vortex formation. Aerodynamic drag reduction close to 24% for the computational approach and 14.8% for the experimental approach by introducing a suction had been obtained.
Harinaldi , Budiarso , Warjito , Engkos A. Kosasih, Rustan Tarakka and Sabar P. Simanungkalit, 2012. Active Technique by Suction to Control the Flow Structure over a Van Model. Journal of Engineering and Applied Sciences, 7: 215-222.