Assessment of a dual-scale approach to LES modeling of propagating interfaces

Deflagration fronts and phase interfaces undergoing phase change are just two examples of interfaces propagating normal to themselves through a background flow field that can be turbulent. To model these propagating interfaces in turbulent flows using a Large Eddy Simulation (LES) approach, a dual scale model based on the volume of fluid method was recently proposed. The model reconstructs the sub-filter interfacial velocity field on a high-resolution overset narrow band mesh and uses it to transport a fully resolved realization of the interface. Unclosed interfacial terms on the LES scale can then be closed by explicit filtering of the fully resolved interface geometry.

In this presentation, we will assess the performance of the dual-scale LES approach by comparing to direct numerical simulation (DNS) results of an initially planar constant speed interface in a triply periodic box of decaying homogeneous isotropic turbulence. We will furthermore compare the dual-scale LES results to an unstructured Cartesian adaptive mesh refinement approach that employs the DNS resolution only in a narrow band surrounding the interface and aggressively coarsens the mesh to the LES resolution away from the interface.