Numerical Prediction of Mixed Convection Flow Regime in Low-Prandtl Number Fluids

Turbulent heat transfer is an extremely complex phenomenon and is critical in scientific and industrial applications. It becomes much more challenging in a buoyancy-influenced flow regime, particularly for non-unity Prandtl number (Pr) fluids. In this article, an effort has been put forward to assess the prediction capabilities of different Reynolds-Averaged Navier-Stokes (RANS) based turbulence models for a mixed convection flow regime. In this regard, a mixed convection flow in a channel is considered for three different Richardson numbers (Ri = 0.25, 0.5, and 1). The considered flow configuration is a parallel plate arrangement with differentially heated side walls. Two different turbulent heat flux models are compared with the available reference Direct Numerical Simulation database. The prediction capabilities for these modeling approaches are assessed and will be extensively discussed in this paper.