LESGO is a parallel pseudo-spectral large-eddy simulation code.

Subgrid scale models

The subgrid scales are modeled using an eddy viscosity model for the deviatoric part of the subgrid stress tensor

\[\tau_{ij} = - 2 \nu_T \tilde{S}_{ij}, \]

where \( \tilde S_{ij} = \frac{1}{2} \left( \partial_j \tilde u_i + \partial_i \tilde u_j \right) \) is the resolved strain rate tensor. The eddy viscosity is usually given using the Smagorinsky relationship \( \nu_T = (C_{s,\Delta} \Delta)^2 | \tilde{S} | \), where the strain rate magintude is \( | \tilde{S} | = \sqrt{ 2\tilde S_{ij} \tilde S_{ij} }\).

LESGO includes five subgrid models to determine the coefficient \( C_{s,\Delta} \):


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