Event Type:

Applied Mathematics and Computation Seminar

Date/Time:

Tuesday, April 10, 2012 - 03:00 to 04:00

Location:

NASH 206

Event Link:

Guest Speaker:

Institution:

Naval Postgraduate School

Abstract:

In our efforts to construct a three-dimensional nonhydrostatic atmospheric model for applications in weather prediction we have developed numerous versions using different numerical methods (continuous Galerkin and discontinuous Galerkin) and time-integrators (explicit, implicit-explicit). It is far more efficient to construct one model that is unified in terms of: 1) numerical methods, 2) time-integrators, and 3) types of flows. Thus we have formulated NUMA (the nonhydrostatic unified model of the atmosphere) as a combined CG/DG model. In addition, NUMA has been designed to solve the equations in a box (as in mesoscale or regional flow), on the

sphere (as required for global atmospheric modeling), as well as possibly even in

urban-scale modeling scenarios (flows over buildings, etc.). Finally, NUMA has been designed to use implicit-explicit (IMEX) methods in all three spatial dimensions (requiring the solution of a very large global sparse linear system) as well as in the vertical direction only which allows the method to scale, on massively parallel computers, as well as the base explicit method). This last point is critical to the success of NUMA and with this latest implementation the DG method can be as competitive as the CG approach. The derivation of this general 1D IMEX implementation will be described in detail and the challenges facing IMEX DG formulations will be discussed.

Host: