[Dr Youssef Hafez]

It is well known that the linear stress-strain rate model for representing the Turbulent stresses via the eddy viscosity concept is not valid under several conditions. For example, linear models do not produce secondary motion due to corners.

The literature is full of several nonlinear Algebraic stress models which vary in their complexities and their efficiencies; however, no one model is known to be accepted by the CFD community (at least to me).

Stress transport models on the other hand have limitations (especially being complex and computationally expensive). So I am not sure if they should be included in this discussion.

What would be the best nonlinear Algebraic Stress model?. I hope your answer is substantiated based on using whatever you suggest or through evidences by other investigations.