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A GENERALIZED EARSM BASED ON A NONLINEAR PRESSURE STRAIN RATE MODEL

Olaf Grundestam
Department of Mechanics, Royal Institute of Technology, KTH SE-100 44 Stockholm, Sweden

Stefan Wallin
Linne FLOW Center, Department of Mechanics Royal institute of technology Osquars Backe 18, Stockholm, Sweden

Arne V. Johansson
Linne FLOW Centre, Dept. of Mechanics, Royal Institute of Technology SE-100 44 Stockholm, Sweden

Аннотация

The use of a pressure strain rate model including terms nonlinear in the strain and rotation rate tensors in an explicit algebraic Reynolds stress model (EARSM) is considered. For 2D mean flows the nonlinear contributions can be fully accounted for in the EARSM formulation. This is not the case for 3D mean flows and a suggestion of how to modify the nonlinear terms to make the EARSM formulations for 2D and 3D mean flows consistent is given. The corresponding EARSM is derived. This is all done in conjunction with the use of streamline curvature corrections emanating from the advection of the Reynolds stress anisotropy. The proposed model is tested for rotating homogeneous shear flow, rotating channel flow and rotating pipe flow. The nonlinear contributions are shown to have a significant effect on the flow characteristics. Finally, model predictions are investigated using a K−ω platform with a change in the dissipation rate production, Pε. It is found that even for a small change of Pε the effect is considerable and it is argued that some of the shortcomings of the model can be attributed to the modelling of Pε (or corresponding Pω).