HR: 0800h
AN: S51D-1034    [Abstracts]
TI: High-Performance Computing and Visualization of Tsunamis and Wind-Driven Waves
AU: * Liu, Y S
EM: liuyingch@mails.gucas.ac.cn
AF: Laboratory of Computational Geodynamics, Chinese Acadmey of Sciences 19 Yu Quan Lu, Beijing, 100049 China
AU: Zhang, H
EM: hzhang@gucas.ac.cn
AF: Laboratory of Computational Geodynamics, Chinese Acadmey of Sciences 19 Yu Quan Lu, Beijing, 100049 China
AU: Yuen, D A
EM: davey@krissy.geo.umn.edu
AF: Dept. of Geology and Geophysics and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0219 United States
AU: Wang, M
EM: shwang1386@gmail.com
AF: Dept. of Geology and Geophysics and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0219 United States
AB: The Sumatran earthquake and the tsunami waves produced have awakened great scientific interest in wave-propagation over undulated bottom topography and along complicated coastlines. The recent hurricane Katrina has also called our attention to shorter period waves near the coast. Analytical approximations are valid over long wavelengths in the far field. For near field regions with complex geography and other complications, such as islands and harbors, numerical simulations must be employed to obtain accurate predictions in time and space. Nowadays using 10**7 to 10**8 grid points become quite routine with massively parallel computers and large RAM and disk memories. Besides tsunamis, river discharges from upstream events and waves driven by hurricanes are also of societal relevance, especially in central China and now also in U.S.A. Using automatic grid generation methods, we have devised a finite-element based code, for the three stages which culminates with the use of the augmented Lagrangian method for the run-up process, as well as the Arbitrary Lagrange- Euler Configuration method to tackle the free surface problem near the seashore. This formulation allows for the wave surface to be self-consistently determined within a linearized framework and is computationally very fast. Our continuous efforts are focussed on seeking novel algorithms and state of art techniques, in order to unravel the mysteries associated with tsunami wave propagation and wind-driven waves in 3-D. We have cast the Navier-Stokes equations within the framework of a compressible model with an equation of state for sea-water. Our formulation allows the tracking and simulation of three stages , principally the formation, propagation and run-up stages of tsunami and waves coming ashore. The sequential version of this code can run on a workstation with 4 Gbyte memory less than 2 minutes per time step for one million grid points. This code has also been parallelized with MPI-2 and has good scaling properties, nearly linear speedup, which has been tested on a 32-node PC cluster. We have employed the actual ocean seafloor topographical data to construct oceanic volume and attempt to construct the coastline as realistic as possible, using 11 levels structure meshes in the radial direction of the earth. In order to understand the intricate dynamics of the wave interactions, we have implemented a visualization overlay based on Amira, a 3-D volume rendering visualization tools for massive data post-processing. The ability to visualize the large data sets remotely is an important objective we are aiming for, as international collaboration is one of the top aims of this research.
UR: http://tomo.msi.umn.edu/~shuom/tsunami
DE: 4564 Tsunamis and storm surges
SC: Seismology [S]
MN: Fall Meeting 2005