  Large eddy simulation (LES) of turbulence in complex geometries and domains
is often conducted with high aspect ratio resolution cells of varying shapes
and orientations. The effects of such anisotropic resolution are often
simplified or neglected in subgrid model formulation. Here, we examine
resolution induced anisotropy and demonstrate that, even for isotropic
turbulence, anisotropic resolution induces mild resolved Reynolds stress
anisotropy and significant anisotropy in second-order resolved velocity
gradient statistics. In large eddy simulations of homogeneous isotropic
turbulence with anisotropic resolution, it is shown that commonly used subgrid
models, including those that consider resolution anisotropy in their
formulation, perform poorly. The one exception is the anisotropic minimum
dissipation model proposed by Rozema et al. (Phys. of Fluids 27, 085107, 2015).
A simple new model is presented here that is formulated with an anisotropic
eddy diffusivity that depends explicitly on the anisotropy of the resolution.
It also performs well, and is remarkable because unlike other LES subgrid
models, the eddy diffusivity only depends on statistical characteristics of the
turbulence (in this case the dissipation rate), not on fluctuating quantities.
In other subgrid modeling formulations, such as the dynamic procedure, limiting
flow dependence to statistical quantities in this way could have advantages.
