Eddy Viscosity Models
This is the most well known means to model the Reynolds stresses. The basic concept takes a recourse to Boussinesq hypothesis that assumes the relationship between the mean velocity gradients and the Reynolds stresses in the following way
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(26.6) |
where
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(26.7) |
And k is the turbulent kinetic energy. Equation (26.6) is valid for incompressible flows. The symbol v t is the turbulent eddy viscosity which is not a fluid property but depends strongly on the state of turbulence. Hence, vt may vay significantly from one point in the flow to another and also from flow to flow.
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