Large eddy simulation of heat and mass transport in turbulent flows. Part 2: Scalar field

摘要

Several subgrid-scale (SGS) scalar flux (τ_(iA)) and unmixedness (λ_(AB)) models are presented for large eddy simulation (LES) of heat and mass transport in turbulent flows. The models are similar to those considered in [Int. J. Heat Mass Transfer, in press] for SGS stresses and are based on the information residing at filtered or resolved field. All closures are implemented "locally" and are assessed a priori and a posteriori via data generated by direct numerical simulations of several nonreacting and reacting turbulent flows. A priori assessment indicates that the local values of τ_(iA) and λ_(AB) obtained by new "serial decomposition" closures are closer to "true" values than those obtained by dynamic-diffusivity and two-parameter mixed models. A posteriori assessment also indicates that the statistics of the scalar field in non-reacting and reacting flows are better predicted by LES when new SGS models are used.