engleski

The Atmospheric Boundary Layer Above Generic Hills: Computational Model of a Unidirectional Body Force-Driven Flow

A computational steady Reynolds-averaged Navier–Stokes model is developed for a neutrally-stratified unidirectional flow in the atmospheric boundary layer (ABL) over generic two-dimensional cosine-shaped hills. Simulations are performed for a hill of a constant height and three different hill slopes. The hill surface is treated as smooth and aerodynamically rough. Atmospheric-boundary-layer inflow profiles for computations of the flow over a hill are generated from the precursor two-dimensional simulations with applied Neumann boundary conditions and an additional body force (wind-source term) introduced into the momentum equation, which value varies with increasing height. This body force ensures the appropriate momentum transport along an empty computational domain and its physical meaning is put in perspective regarding the realistic twisted ABL. The results obtained using the standard constants of the standard k−ε turbulence model are compared to the results obtained using several sets of modified constants of this same turbulence model, to evaluate the influence of the inactive turbulence. The results generally indicate good agreement with the characteristics of strong flow over hills. While the modified turbulence constants yield better results for the ABL flow over flat terrain, the flow characteristics over a hill are more accurate when the standard constants of the standard k−ε turbulence model are used.

Body force-driven flow ; Cosine-shaped hill ; Inactive turbulence ; Neutrally-stratified atmospheric boundary layer ; RANS turbulence modelling

nije evidentirano