Large eddy simulation of transitional boundary layer flow with two-parameter mixed models*

Large eddy simulation of a transitional boundary layer flow is performed to assess modified two-parameter mixed models. Because energy transfer between the grid-scale and subgrid-scale has to be modeled to characterize a transitional boundary layer flow, we combine the scale-similarity model and eddy viscosity model as a mixed model. For the proposed mixed models, the two model coefficients are determined by dynamic procedures and the effects of a stress tensor that involves the interaction between the resolved and unresolved scales are considered to estimate the proper energy exchange between large-scales and subgrid-scales. The proposed mixed model with the dynamic Smagorinsky model shows improved prediction in the skin-friction coefficient and shape factor in a transition region, compared to the earlier studies with various subgrid-scale models. The energy dissipation predicted by the present mixed model shows a good agreement with a filtered direct numerical simulation data, although the magnitude of the modeled dissipation is slightly underestimated.