Large eddy simulation of heat transfer around a square cylinder using unstructured grids

International audienceThis paper presents a method of large eddy simulation on unstructured grids designed to predict the wall heat transfer in typical aeronautical applications featuring turbulent flows and complex geometries. Two types of wall treatment are considered: a wall-function model using a full tetrahedral grid and a wall-resolved method computed on a hybrid tetrahedral-prismatic grid. These two approaches are tested against the square cylinder case at moderate Reynolds number (Re = 22 050) where many reference data are available for flow dynamics and heat transfer. Both predict accurately the unsteady flow around the cylinder and in its near-wake but only the wall-resolved approach reproduces the Nusselt number global value and its spatial distribution around the cylinder wall. This latter method is used to investigate the coupling between periodic vortex shedding and wall heat transfer using a phase-averaged analysis. Nomenclature CD = drag coefficient C f = algebraic friction coefficient Cp = pressure coefficien