A dual-eddy EMMS-based turbulence model for laminar–turbulent transition prediction

Abstract

Turbulence is a century-old physics problem, and the prediction of laminar–turbulent transition remains a major challenge in computational fluid dynamics (CFD). This paper proposes a new conceptual multiscale-structure flow system consisting of a nonturbulent part and two types of turbulent eddies with different properties. The stability criterion for turbulent transition flows, based on the principle of compromise-in-competition between viscosity and inertia, is used to obtain model closure. The multiscale-structure concept and stability criterion are the characteristics of the dual-eddy energy-minimization multiscale (EMMS)-based turbulence model. The solved heterogeneous structure parameters and energy dissipation rate are analyzed, which reveal the laminar–turbulent transition process. To validate the dual-eddy EMMS-based turbulence model, three benchmark problems, namely, the transitional flows over the flat plate boundary layer with zero pressure gradient, NACA0012, and Aerospatiale-A airfoils, were simulated. The simulation was performed by combining the optimized results from the proposed model with the equations of the well-known k−ω shear stress transfer (SST) turbulence model. The numerical results show that the dual-eddy EMMS-based turbulence model improves the prediction in the laminar–turbulent transition process. This demonstrates the soundness of using the multiscale-structure concept in turbulent flows to establish the turbulence transition model by considering the principle of compromise-in-competition between viscosity and inertia.