CFD STUDY OF FLOW AROUND AHMED BODY

This paper presents a numerical study of flow past an Ahmed body using Improved Delayed Detached Eddy Simulations (IDDES). Ahmed body with straight-back (zero rear slant angle) is used for the analysis. Experimental studies have been conducted in the wake of such car model using two-dimensional optical techniques or at fixed locations. The CFD study can be used to bridge the gap in the experimental data, by simulating the complete three-dimensional flow field. The velocity and turbulence characteristics predicted by the simulation are compared with experimental results and are presented with detailed discussions. The coherent structures in the wake flow are educed using vortex identification techniques. Their effect on the aerodynamics of the Ahmed body is presented with pertinent analysis. Due to the complexity of the flow field, this present study could also be used as a benchmark for assessing the performance of IDDES model in complex flow fields.