Computational Simulations of the Thermally Stratified Atmospheric Boundary Layer above Hills

Some characteristics of thermal effects in numerical simulations of the atmospheric boundary layer (ABL) flow which develops above hilly terrain are discussed in this paper. The differences and unstable stratification effects between the windward and leeward sides of a hill model were investigated for different upwind velocity. Particularly, the buoyancy effects on the structure of turbulent boundary layers in a wide range of stability conditions were studied. Steady Reynolds-averaged-Navier-Stokes (RANS) equations along with the SST k-ω turbulence model are used for Computational Fluid Dynamics (CFD) simulations of the thermally stratified flow and turbulence above hills. The computational results indicate an improved accuracy of the turbulent heat transfer for engineering applications including flow separation and reattachment, rotation, and buoyancy.