A dynamic subgrid-scale eddy viscosity model

TLDR

Eddy viscosity subgrid‑scale stress models in large‑eddy simulations struggle to represent different turbulent fields with a single universal constant, especially in rotating or sheared flows, near solid walls, or transitional regimes. The study introduces a new eddy viscosity model that alleviates these drawbacks. The model computes its coefficient dynamically during the simulation using an algebraic identity between subgrid‑scale stresses at two filtered levels and the resolved turbulent stresses. The model yields subgrid‑scale stresses that vanish in laminar flow and at solid boundaries, exhibit correct near‑wall asymptotics, and produce large‑eddy simulation results that agree well with direct numerical simulation data for transitional and turbulent channel flow.

Abstract

One major drawback of the eddy viscosity subgrid-scale stress models used in large-eddy simulations is their inability to represent correctly with a single universal constant different turbulent fields in rotating or sheared flows, near solid walls, or in transitional regimes. In the present work a new eddy viscosity model is presented which alleviates many of these drawbacks. The model coefficient is computed dynamically as the calculation progresses rather than input a priori. The model is based on an algebraic identity between the subgrid-scale stresses at two different filtered levels and the resolved turbulent stresses. The subgrid-scale stresses obtained using the proposed model vanish in laminar flow and at a solid boundary, and have the correct asymptotic behavior in the near-wall region of a turbulent boundary layer. The results of large-eddy simulations of transitional and turbulent channel flow that use the proposed model are in good agreement with the direct simulation data.