Turbulent Decay in Strongly Accelerated Flows

Jonas Larsson

I'm looking at the design of a contraction in front of a wind-tunnel. The contraction has an inlet/outlet area ratio of about 6 and hence gives a strong accelaration of the flow. This strong accelaration leads to a reducion of stream-wise turbulent fluctuations and an amplification of corss-stream-wise turbulent fluctuations. There are correlations developed by Bradshaw to estimate this effect.

I would like to do a CFD computation including the contraction and I'm a bit hesitant if the turbulent decay/amplification in this type of strongly accelarated flows can be captured with a RANS based turbulence models. Obviously eddy-viscosity models like k-epsilon or k-omega can not capture the anisotropic effects. But do this type of models have any chance to capture the total effect on turbulence intensity (I doubt it myself)? Will RSM model it correctly? Or should I skip all RANS based model?