Does the eddy viscosity take zero, when flow velocity is very low?

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Gianluca Argentini

Dear Hassan, in the Boussinesq model of turbulence, (dynamic) eddy viscosity e depends on mean flow velocity v and if v = 0 then e = 0, even if (static) physical viscosity is not zero. See attached paper as reference for a good presentation. Gianluca

Rafik Absi

eddy viscosity is equal to zero near a wall (solid surface) in turbulent boundary layers and near a free surface in open channel flows

Please read our article Assessment of models for velocity distribution in turbulent smooth-wall open channel flows https://www.tandfonline.com/doi/abs/10.1080/09715010.2019.1677180.

The eddy viscosity is equal to zero near the wall (Velocity =0) and free surface (Velocity =/=0).