Numerical Study of the Flow Around a Bus-Shaped Body

Abstract

Flow around a simplified bus is analyzed using large-eddy simulation. At the Reynolds number of 0.21×106, based on the model height and the incoming velocity, the flow produces features and aerodynamic forces relevant for the higher (interesting in engineering) Reynolds number. A detailed survey of both instantaneous and time-averaged flows is made and a comparison with previous knowledge on similar flows is presented. Besides the coherent structures observed in experimental and previous numerical studies, new smaller-scale structures were registered here. The mechanisms of formation of flow structures are explained and the difference between instantaneous and time-averaged flow features found in the experimental observations is confirmed. Aerodynamic forces are computed and their time history is used to reveal the characteristic frequencies of the flow motion around the body. A comparison is made of pressure and velocity results with experimental data and shows fairly good agreement.