Minimum-dissipation model and symmetry-preserving discretization for scalar transport in a turbulent flow

This work extends the minimum-dissipation model of large-eddy simulation and symmetry-preserving discretization to account for active or passive scalar transport and complex physical mechanisms.This novel scalar-minimum-dissipation model exhibits several desirable properties. It includes the effect of scalar transport, in addition to shear, on the suppression and production of turbulence. It switches off at no-slip walls, ensuring accurate capture of near-wall flow behavior without needing a wall model. It also switches off in laminar and transitional flows so that it is capable of predicting laminar-turbulent transition. The new scalar-minimum-dissipation model combined with the symmetry-preserving discretization is successfully tested in a differentially heated cavity in OpenFOAM. The results show that the symmetry-preserving discretization significantly improves predictions of flow quantity and heat transfer on highly stretched meshes.