Simulating Atmospheric Boundary Layer Turbulence with Nek5000/RS

Abstract

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Advanced Turbulence Models for Large-Scale Atmospheric Boundary Layer Flows

“…Results obtained with the MFEV/HPF approach led to converged results with increasing resolution. In addition, the obtained profiles were almost identical for different values of Re as well as of z + 1 as reported in [4]. Results obtained with the MFEV/SMG approach also demonstrate convergence with increasing resolution as well as asymptotic convergence with Re and z + 1 .…”

“…We have extended the range of our SGS modeling approaches, in the context of the MFEV [5], to include the solution of an SGS TKE equation. In our earlier ANL report [4], we discussed the modeling approaches for the following:…”

“…In the earlier report [4], two different types of boundary conditions were used in Nek5000/NekRS at the bottom boundary representing the lower wall. These boundary conditions (BCs) were no-slip and traction BCs.…”

“…As described in [4], this traction boundary condition in Nek is imposed at the first grid point in the vertical direction, which is assumed to be a point inside the log-layer at a location z = z 1 , where the boundary condition for the vertical velocity component is defined to be zero. For this reason the second term in Eq.…”

“…In our earlier ANL report [4], we demonstrated our newly developed subgrid-scale (SGS) models based on highpass filter (HPF), mean-field eddy viscosity (MFEV), and Smagorinsky (SMG) with no-slip and traction boundary conditions, provided with low-order statistics, convergence, and turbulent structure analysis. In this report, we extend the range of our SGS modeling approaches in the context of MFEV [5], to include the solution of an SGS turbulent kinetic energy (TKE) equation.…”