A New Semi-Implicit Time Integration Scheme for the Time-Dependent Atmospheric Boundary Layer Environment (ABLE) Model

Report No. ARL-TR-7428
Authors: Benjamin T MacCall, Yansen Wang, and Wen-Yih Sun
Date/Pages: September 2015; 28 pages
Abstract: The time integration scheme demonstrated for the nonlinear shallow water equations has been extended to the 3-dimensional Navier-Stokes system and implemented as a time-dependent, finite-volume, convection-diffusion scheme in a new direct numerical simulation code. The model was compared with other simulation and laboratory results of lid-driven cavity flows with Reynolds numbers of Re=1000, 3200, and 10,000 to assess simulation of boundary forced flows and generation of intermittent flow structures. The generation and shedding of the various flow vortices, including Taylor-Goertler like (TGL) vortices, impact the velocity variances and covariance as observed, though the vortex shedding frequency is greater than observed in the laboratory. The scheme's low implicit diffusion, reduced need for explicit smoothing, and straightforward parallel implementation make it a good candidate for incorporating into finite-volume, large-eddy simulation for highly time-dependent atmospheric boundary layer flow.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2015