Large Eddy Simulation of Canonical Atmospheric Boundary Layer Flows With the Spectral Element Method in Nek5000

Simulation of turbulence in the atmospheric boundary layer (ABL) is challenging due to the wide range of turbulent scales in the flow. To leverage the currently available computational power for high-resolution simulation of atmospheric turbulence, fluid solvers that scale well on large compute clusters are required. We present a new large eddy simulation (LES) framework based on the open-source solver Nek5000, which uses the highly parallelizable spectral element method (SEM) for spatial discretization. We document the Nek5000 framework for LES of thermally stratified atmospheric boundary layers and present results from the solver for neutral, convective, and stably stratified boundary layers. To verify that the solver is capable of accurately representing important features of the ABL, we compare our results to an established LES solver and find very good agreement in statistics as well as coherent structures. We also compare results with two different subgrid-scale models and conclude that one based on the subgrid-scale turbulent kinetic energy performs better together with the SEM.