Passive Scalar Transport Modeling for Hybrid RANS/LES Simulation

Abstract

A transport model for hybrid RANS/LES simulation of passive scalars is proposed. It invokes a dynamically computed subgrid Prandtl number. The method is based on computing test-filter fluxes. The formulation proves to be especially effective on coarse grids, as occur in DES. After testing it in a wall resolved LES, the present formulation is applied to the Adaptive DDES model of Yin et al. (Phys. Fluids 27, 025105 2015). It is validated by turbulent channel flow and turbulent boundary layer computations. Abstract A transport model for hybrid RANS/LES simulation of passive scalars is proposed. It invokes a dynamically computed subgrid Prandtl number. The method is based on computing test-filter fluxes. The formulation proves to be especially effective on coarse grids, as occur in DES. After testing it in a wall resolved LES, the present formulation is applied to the Adaptive DDES model of Yin et al. (2015). It is validated by turbulent channel flow and turbulent boundary layer computations.

Production‐limited delayed detached eddy simulation of turbulent flow and heat transfer

“…A local and dynamic Pr sgs formation was used to model passive scalar transport with an adaptive DDES model . The results show that the Pr sgs ranges from 0.15–0.4 . It was noted that a log‐layer mismatch of the temperature appeared using the adaptive DDES model, when the Pr t was globally set to be 0.9.…”

“…A priori tests of homogeneous shear flow show that the Pr sgs ranges from 0.3–0.6, and a priori tests of channel flow demonstrate that the Pr sgs is ∼0.5 near the centreline . A local and dynamic Pr sgs formation was used to model passive scalar transport with an adaptive DDES model . The results show that the Pr sgs ranges from 0.15–0.4 .…”

“…The results show that the Pr sgs ranges from 0.15–0.4 . It was noted that a log‐layer mismatch of the temperature appeared using the adaptive DDES model, when the Pr t was globally set to be 0.9. Yin and Durbin used a dynamic Pr t to let the subgrid model adapt to the flow and to the grid, but the dynamic Pr t makes the model complex and difficult to conduct.…”

“…It was noted that a log‐layer mismatch of the temperature appeared using the adaptive DDES model, when the Pr t was globally set to be 0.9. Yin and Durbin used a dynamic Pr t to let the subgrid model adapt to the flow and to the grid, but the dynamic Pr t makes the model complex and difficult to conduct. Therefore, a novel model that can be conducted easily is needed to eliminate the LLM issue.…”

Adaptive Detached Eddy Simulation and Passive Scalar Transport Modeling for Hybrid RANS/LES

“…To extend adaptive DES to compressible flow and heat transfer, a passive scalar transport model is proposed for Hybrid RANS/LES (Yin and Durbin, 2016b). This too is an adaptive model.…”