Large-Eddy Simulation of Stably-Stratified Flow Over a Steep Hill
Large-eddy simulation (LES) is used to simulate stably-stratified turbulent boundary-layer flow over a steep two-dimensional hill. To parametrise the subgrid-scale (SGS) fluxes of heat and momentum, three different types of SGS models are tested: (a) the Smagorinsky model, (b) the Lagrangian dynamic model, and (c) the scale-dependent Lagrangian dynamic model (Stoll and Port,-Agel, Water Resour Res 2006, doi:10.1029/2005WR003989). Simulation results obtained with the different models are compared with data from wind-tunnel experiments conducted at the Environmental Flow Research Laboratory (EnFlo), University of Surrey, U.K. (Ross et al., Boundary-Layer Meteorol 113:427-459, 2004). It is found that, in this stably-stratified boundary-layer flow simulation, the scale-dependent Lagrangian dynamic model is able to account for the scale dependence of the eddy-viscosity and eddy-diffusivity model coefficients associated with flow anisotropy in flow regions with large mean shear and/or strong flow stratification. As a result, simulations using this tuning-free model lead to turbulence statistics that are more realistic than those obtained with the other two models.
Keywords: Large-eddy simulation ; Stable stratification ; Subgrid-scale modelling ; Two-dimensional hill ; Atmospheric Boundary-Layer ; Dependent Dynamic-Model ; Neutral Turbulent-Flow ; Subgrid-Scale Models ; Complex Terrain ; Channel Flow ; Wavy Surface ; Transport
Record created on 2011-01-27, modified on 2016-08-09