Question

Leonard stresses are caused by ____________

(a) The SGS eddies

(b) The effects at the resolved scale

(c) The effects of the unresolved variables

(d) The combined effect of the SGS eddies and the resolved scale

This question was addressed to me in unit test.

My question is taken from Turbulence Modelling in portion Turbulence Modelling of Computational Fluid Dynamics

Answer 1

The correct option is (b) The effects at the resolved scale

Easy explanation: The Leonard stress terms occur because of the term \(\rho\overline{\overline{u_i}\overline{u_j}}\). These are both the resolved velocities. So, we can conclude that the cause for Leonard stresses is the effects at the resolved scale.