Two level simulation of Schmidt number effect on passive scalar transport in wall-bounded turbulent flows

In this study, the two-level simulation (TLS) modeling strategy developed earlier for momentum mixing is assessed in turbulent flows with passive scalar and transport. Compared to conventional algebraic transport equation based subgrid-scale closures large-eddy (LES), where effects of unresolved small scales (SS) motion on large (LS) are modeled, TLS model, both explicitly evolved a coupled two-scale decomposition method called TLS. Earlier studies demonstrated ability SS model simulate high Reynolds number wall-bounded reasonable LS grid resolution. present extended channel flows. A comprehensive priori assessment performed using direct numerical datasets fully flow at frictional Reτ=395 Schmidt numbers Sc= 1 4. This carried out study evolution field physical spectral space also assess prediction quantities relevant scalars such as dissipation rate, counter-gradient transport, backscatter. is, then, used posteriori near-wall hybrid TLS–LES approach model.