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Hello,

I use Smagorinski model for horizontal turbulence and Nezu and Nakagawa mixing length model for vertical turbulence. Coefficient for vertical diffusion of velocities is 0.01; coefficient for horizontal diffusion of velocities is the same (0.01).

How are these coefficients taken into account in the calculation? Is the coefficient for horizontal diffusion of velocities used as Cs in the Smagorinski formula? Or is it viscosity which is added to the value calculated by the Smagorinski formula?

How is the coefficient for vertical diffusion of velocities used in the Nezu and Nakagawa equation?

Best regards,
Tatiana

Hello,

First make sure to take the enclosed corrected subroutines for Smagorinski. You will see that CS is hardcoded in them, you may change it if you want. Then this turbulent viscosity is added to the laminar viscosity which is considered in this case to be the coefficient for horizontal diffusion of velocities that you give, so prefer 1.D-6 rather than 0.01. Same thing for Nezu and Nakagawa.

With best regards,

Jean-Michel Hervouet