Numerical simulation of weakly turbulent heat transfer over cavities at low Prandtl numbers

Heat transfer investigations at low Prandtl number values are of interest for different applications, but reliable physicalmodels for turbulent convection in these fluids are still missing. In the present study forced convective heat transfer isinvestigated numerically for weakly turbulent flow in a streamwise periodic channel with cavities. Simulations are performedfor different values of the Prandtl number, with the focus on the case with Prandtl number equal to 0:025, which representsliquid lead-bismuth eutectic (LBE). In the paper the main features of the mean and instantaneous flow field are presentedtogether with first order statistics. The influence of flow separation mechanisms and turbulent mixing on local and globalheat transfer rates are discussed, for both isoflux and isothermal boundary conditions (BCs hereafter). The numericalcode used for the simulations is based on a second order, finite volume algorithm, implemented over structured, curvilinearmesh. This work aims to contribute to the development of physical model of turbulent convection for low Prandtl numberfluid flows, by providing information for both velocity and temperature fields.