Published: Oct. 23, 2014

A HEVI Time-splitting Scheme for Idealized Discontinuous Galerkin Non-Hydrostatic Atmospheric Simulations

 

 

Lei Bao

Applied MathematicsUniversity of Colorado Boulder

Date and time: 

Thursday, October 23, 2014 - 1:00pm

Location: 

ECCS 123

Abstract: 

A non-hydrostatic (NH) atmospheric model is greatly needed. The arrival of peta-
scale computing resources facilitates the development of a high resolution NH at-
mospheric model. We use the full flux-form of the compressible Navier-Stokes (NS)
equations to characterize the idealized NH atmosphere and choose discontinuous
Galerkin (DG) method for the spatial discretization. One of the most challenges
in the NH scale is the tiny time-step size of the explicit time integration scheme,
from the fast moving acoustic waves and the gravity waves, and the large aspect
ratio between horizontal-vertical grid spacing, usually 100-1000. To address this
diculty, we consider a horizontal-explicit-vertical-implicit (HEVI) time splitting
scheme to relax the CFL condition to the horizontal grid spacing. In the rst part
of this study, we use the shallow water equations on the cubed-sphere to study
the horizontal aspects that can be found in the full 3D NH mode. We checked
the conservation property and the performance of LDG numerical diusion in the
shallow-water system. Next, the HEVI time-splitting scheme is explored using the
2D compressible NS/Euler system as the testbed. The numerical results from a
suite of NH benchmark test-cases show that HEVI scheme performs well in the
DG-NH framework. The ultimate goal of this study is to extend the HEVI scheme
for the global DG-NH model and validate the model using the dynamical-core-
model-inter-comparison-project (DCMIP) tests.

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