Eddy viscosity transport model for turbulent flow

Abstract

An eddy viscosity transport model that is integrable to no-slip walls is described. The transport equation accommodates significant departure of the turbulence from equilibrium. The model uses an elliptic relaxation equation to avoid a need for damping functions; nonlocal wall effects are produced by solving the elliptic equation. Length scales are determined locally, without reference to distance to a surface. The model bifurcates from a laminar to a turbulent solution at a reasonable critical Reynolds number in plane channel flow. An assessment of the model is provided via boundary layer computations: these show that it behaves well in zero and adverse pressure gradients, although premature separation occurs in a strong adverse pressure gradient. Good results are obtained for the trailing edge separation bubble of an aerofoil at large angle of attack.