Bluff body asymmetric flow phenomenon-real effect or solver artefact?

This paper describes a CFD investigation into the flow over the cab of a bluff-fronted lorry.rnSeveral different simulations were undertaken, using the commercial codes: CFX, Fluent and PowerFLOW.rnUsing the k - e turbulence model, the flow over the cab was symmetric, however, using more accuraternturbulence models such as the RNG k - e model or the Reynolds Stress Model, the flow was asymmetric.rnThe paper discusses whether this phenomenon is a real effect or whether it is a solver artefact and thernstudy is supported by experimental evidence. The findings are preliminary, but suggest that it has arnphysical origin and that it may be aspect ratio-dependent.