Scientific Computing Seminar

Date:

Wednesday, August 25, 2004

Time:

2:00pm-3:00pm

Location:

50B-4205

Seminar Speaker:

Yu-heng Tseng
Johns Hopkins University

Title:

On the Development of the Immersed Boundary Method and its Application to High Performance Ocean Modeling

Abstract:

An efficient immersed boundary method (IBM) for simulating turbulent flows in complex geometries is presented. A boundary condition is enforced through a ghost cell method. The reconstruction procedure allows systematic development of numerical schemes to treat the immersed boundary while preserving the overall accuracy of the base solver. The accuracy is validated using flow past a circular cylinder, large eddy simulation of turbulent flow over a wavy surface and geophysical flow over a three-dimensional bump. Numerical results are compared with experimental data and boundary-fitted grid results. The method is further extended to an existing non-hydrostatic ocean model (DieCAST) to simulate general circulation in the vicinity of Monterey Bay area, California. The circulation in this area is driven by a variety of mechanisms. Satellite images often show a cyclonic eddy in the bay and an anti-cyclonic eddy outside the bay during spring and summer. We compare the simulation results with observed mooring data and compare the simulated upwelling with the satellite images. The mean currents follow the annual cycle of the seasonal circulation. Finally, the IBM is implemented in Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier-Stokes Simulator (SUNTANS) currently to better represent complex coastal topography. In this project, we are developing a non-hydrostatic, unstructured, parallel coastal ocean model. The code is written in the C language and the message-passing interface (MPI) is employed for the parallel algorithm.

Sponsor of Seminar:

Chris Ding

Scientific Computing

Contact Esmond G. Ng EGNg@lbl.gov