Question

Cross-stresses are caused by ___________

(a) Convection term

(b) Resolved flow

(c) SGS eddies

(d) Interaction of SGS eddies and resolved flow

The question was asked in a job interview.

This key question is from Turbulence Modelling topic in section Turbulence Modelling of Computational Fluid Dynamics

Answer 1

The correct option is (d) Interaction of SGS eddies and resolved flow

For explanation: The cross-stress terms are caused by the combination of the filtered function (Φ) and the eddy function (Φ’). They are given by \(\rho\overline{\overline{u_i}u_j^{‘}} + \rho\overline{u_i^{‘}\overline{u_j}}\). So, we can say that they are caused by the interaction of SGS eddies and resolved flow.