A mixing model for turbulent flows based on parameterized scalar profiles

In this paper the closure of molecular mixing in turbulent reactive flows is addressed in the context of probability density function methods. It is safe to say that the lack of a general and accurate mixing model is a major source for uncertainties in turbulent combustion simulation. Here, we propose a model based on constructing statistical distributions of one-dimensional scalar profiles, i.e., fluid particles are associated to parameterized scalar profiles (PSP). Opposed to previous approaches, the PSP model results in a simple formulation and is able to produce very accurate results at low computational cost. For validation, a two-scalar mixing problem in homogeneous isotropic turbulence was used. The accuracy of the PSP model was demonstrated by comparison with direct numerical simulation data and confirms that the intrinsic physical assumptions are justified.