Buoyancy effects on the wake behind a heated obstacle immersed in a turbulent boundary layer

The effects of buoyancy on the wake behind a two-dimensional (2-D) heated obstacle immersed in a turbulent boundary layer have been examined both experimentally and numerically in an effort to understand the thermal release over complex terrain in an idealized environmental flow. Emphasis was placed on clarifying the modification of the production agencies of the turbulence kinetic energy, resulting both from the direct and indirect buoyant contributions. Buoyancy altered the mean velocity field along the extent of the recirculating region and resulted in a reduction of the turbulent kinetic energy in the vicinity of the obstacle and, through an enhanced shear production, a growth downstream. Buoyant production of turbulent kinetic energy dominated the shear production outside the recirculating region, where the temperature variance was significant. Numerical predictions obtained by a recent buoyancy-extended κ-ε model were found to give the analogous properties of buoyant motion appearing in the experimental results.