Subgrid scale modeling of the equation of state for turbulent flows under supercritical conditions

The focus of this work is to develop subgrid models for the filtered equation of state for large eddy simulation (LES) of supercritical mixing. The conventional LES treatment of directly computing the filtered density in terms of other filtered quantities results in significant modeling errors. To alleviate this problem, two different approaches are investigated - the gradient-based approach, which seeks to establish a model based on the correlation between the subgrid term and the property gradients in the flow field, and the mixing-based approach, which models the subgrid term as a beta function of the mixture fraction and scalar dissipation rate. Reduction in modeling errors by up to 40% is achieved with the models developed and new insights into the physics of these subgrid contributions are gained.