Many mixing processes in engineering applications are turbulent. At high‐Schmidt regime, the scalar scales are much lower than those of the velocity field, making difficult instantaneous measurements and direct numerical simulation for studying systems of practical interest. The use of large eddy simulation (LES) for analyzing transport and mixing of passive and reactive scalars at high‐Schmidt (Sc) regime is addressed in this article. We present two different approaches for studying scalar transport and mixing in LES: the conventional approach is based on the modeling of the unclosed subgrid‐scale scalar flux term in the filtered scalar equation by models commonly used for high‐Sc flows. The second approach presented in this review for dealing with high‐Sc flows is based on the use of a filtered mass density function (FDF) of the scalar field. Conclusions are presented about the relative merits of the two approaches.
Part of the book: Numerical Simulation