Atmospheric boundary layers

Recent developments in large-eddy simulation of thermally stratified atmospheric boundary layers (ABLs) are achieved in collaboration by Drs. Mohanan, Mukha, Brethouwer, Schlatter, Henningson and Svensson. Consolidating the code developments of Mohanan and Mukha, all necessary software components for ABL simulations in Nek5000 have been put in place, such as subgrid scale models and wall-stress boundary conditions.

Two canonical cases from the literature have been setup, corresponding to stable and unstable stratification regimes, respectively. These are an important stepping stone for simulating the complete diurnal cycle. Currently, both cases are being simulated using different combinations of grid resolutions and model selections. Preliminary results show good agreement with reference data from the literature.

Figure: Inclined temperature fronts in a stably stratified ABL.

Figure: Mean velocity (left) and potential temperature (right) profiles in a convective boundary layer.

Reference: Mukha et al. WALL-MODELLED LES USING HIGH- AND LOW-ORDER CFD CODES: APPLICATION TO A FLAT-PLATE BOUNDARY LAYER, TSFP-12, 2022