CMS-Flow:Subgrid Turbulence Model

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Subgrid Turbulence Model

In CMS-Flow eddy viscosity is calculated as the sum of the kinematic viscosity , the current-related eddy viscosity and the wave-related eddy viscosity

       

The wave contribution is included using the equation of Kraus and Larson (1991)

     

where is an empirical coefficient (default is 0.5), and is the wave bottom orbital velocity and is the water depth.

The current-related eddy viscosity is calculated as a function of the flow gradients, and the bottom shear stress

     

where is a base value approximately equal to the kinematic viscosity, is an empirical coefficient, is an empirical coefficient (Smagorinsky coefficient), is the local cell area, and is equal to

     



References

LARSON, M.; HANSON, H., and KRAUS, N. C., 2003. Numerical modeling of beach topography change. Advances in Coastal Modeling, V.C. Lakhan (eds.), Elsevier Oceanography Series, 67, Amsterdam, The Netherlands, 337-365.


CMS-Flow