Scale resolving simulations of flow past a heated sphere using non-linear eddy viscosity closure

The partially-averaged Navier-Stokes (PANS) method of turbulence computations has been employed in recent years to perform scale-resolving simulations of various canonical as well flows of practical interest. While in most flows PANS shows improvements over the Reynolds-averaged Navier-Stokes (RANS) method, further scope of improvement still exists, especially in massively separated flows, wherein the linear eddy viscosity assumption is suspected to misrepresent some essential flow physics. With the motivation to address this shortcoming, we augment the PANS methodology using a non-linear (quadratic) constitutive equation. We examine the performance of this enhanced PANS methodology in flow past a heated sphere at Reynolds number of 10000. We find that the non-linear PANS methodology shows improvements over it conventional counterpart (PANS using linear eddy viscosity assumption) in terms of several hydrodynamic (drag and pressure profiles over the sphere surface, axial and transverse velocity profiles and wake structures), as well as some temperature-related flow features (mean temperature profiles around the sphere and Nusselt number). In this talk these results along with some pertinent explanations and insights will be presented.