Design of residual-based unresolved-scale models using time-averaged data

Abstract

The Large Eddy Simulation of high Reynolds number wall-bounded flows, has grid refinement requirements in near-wall regions similar to those of DNS. The feasibility of such computations is restricted by their elevated costs and therefore alternate solutions must be employed. While several methods to couple LES and RANS have been proposed, most of them employ complicated techniques to combat issues that stem from the inconsistencies introduced by the arbitrary nature of the coupling methods. The aim of this research is to propose a consistent hybrid framework based on a Variational Multiscale Method (VMM) formulation of the Navier-Stokes equations for turbulence computation; where a residual-based algebraic expression for an SGS model will be employed as a coupling term. While, the final solution will be obtained under an LES scheme, the SGS model will contain information drawn from reference data in an overlapping domain. Since the VMM results in an SGS model which depends on the large-scale residual, the coupling will effectively vanish within sufficiently resolved regions without the need of additional controlling terms. The expected result is therefore to demonstrate that reference-data-enriched LES is possible with a solid understanding of the behavior of the proposed SGS models as a basis for future work.