Turbulent diffusivity closures and large eddy simulation models

A turbulent diffusivty closure representing the effects of viscous dissipation and diffusion can be passed via the closure keyword.

See turbulence closures and large eddy simulation for more details on turbulent diffusivity closures.

Constant isotropic diffusivity

To use constant isotropic values for the viscosity ν and diffusivity κ you can use ConstantIsotropicDiffusivity

closure = ConstantIsotropicDiffusivity(ν=1e-2, κ=1e-2)

Constant anisotropic diffusivity

To specify constant values for the horizontal and vertical viscosities, $\nu_h$ and $\nu_v$, and horizontal and vertical diffusivities, $\kappa_h$ and $\kappa_v$, you can use ConstantAnisotropicDiffusivity

closure = ConstantAnisotropicDiffusivity(νh=1e-3, νv=5e-2, κh=2e-3, κv=1e-1)

Smagorinsky-Lilly

To use the Smagorinsky-Lilly LES closure, no parameters are required

closure = SmagorinskyLilly()

although they may be specified. By default, the background viscosity and diffusivity are assumed to be the molecular values for seawater. For more details see SmagorinskyLilly.

Anisotropic minimum dissipation

To use the constant anisotropic minimum dissipation (AMD) LES closure, no parameters are required

closure = AnisotropicMinimumDissipation()

although they may be specified. By default, the background viscosity and diffusivity are assumed to be the molecular values for seawater. For more details see AnisotropicMinimumDissipation.