A Localized Artificial Diffusivity Method for High Density Ratio Multimaterial Flows

High-order compact finite difference schemes’ spectral-like accuracy is well suited for capturing turbulent mixing, but additional stabilization is needed to capture jumps in material properties in multimaterial flows. Localized artificial diffusivity (LAD) is a type of diffuse interface method where artificial fluid properties are added at material interfaces and shocks for stabilization. LAD has shown success with high-order compact finite difference schemes to maintain accuracy in multimaterial flows, but traditional methods struggle for very large density ratios because of the offset between gradients in mass fraction and density. We present a novel LAD method that uses both the volume and mass fractions to compute species diffusivities. This ensures stability and accuracy for simulations with very large density ratios. The strength of the proposed scheme is validated on a suite of test problems.