A test case for large-eddy simulation in vehicle aerodynamics

Flow around a simplified bus was computed using large-eddy simulation (LES) with intention to gain better understanding of this flow and to make a data base for validation of Reynolds-averaged Navier-Stokes equations (RANS) and hybrid RANS-LES simulations. Transient quantities such as dominating frequencies and variance were studied as well as time-averaged quantities. Velocity and pressure results were compared with the experimental data. Coherent structures were visualized and their positions were. determined. Time-averaged Reynolds stresses were computed and the largest resolved turbulent kinetic energy was found in the recirculating flow close to the leading edges and in the lower part of the wake.