7. Turbulence modeling

For the sake of simplicity, this section will only deal with mixture-length models, and in particular the Baldwin-Lomax model.

These models are based on the Boussinesq hypothesis, which consists in defining, by analogy with molecular viscosity, a turbulent viscosity μ _t . This viscosity is then expressed as a function of a mixing length, according to the Prandtl approximation.

Over the last few decades, this type of turbulence modeling has benefited from a number of significant improvements, particularly with regard to the expression of the mixing length L _mix .

The general expression of the Reynolds equation is :