Subgrid-scale models for large-eddy simulation of rotating turbulent flows*

This paper discusses subgrid models for large-eddy simulation of anisotropic flows using anisotropic grids. In particular, we are looking into ways to model not only the subgrid dissipation, but also transport processes, since these are expected to play an important role in rotating turbulent flows. We therefore consider subgrid-scale models of the form $ \tau = -2\nu_t S + \mu_t (S \Omega-\Omega S) $, where the eddy-viscosity $\nu_t$ is given by the minimum-dissipation model, $\mu_t$ represents a transport coefficient; $S$ is the symmetric part of the velocity gradient and $\Omega$ the skew-symmetric part. To incorporate the effect of mesh anisotropy the filter length is taken in such a way that it minimizes the difference between the turbulent stress in physical and computational space, where the physical space is covered by an anisotropic mesh and the computational space is isotropic. The resulting model is successfully tested for rotating homogeneous isotropic turbulence and rotating plane-channel flows.