HR: 12:05h
AN: OS21D-08    [PDF]
TI: Numerical Modeling of Generation of Surface Water Waves by Motion of the Drowned Soil
AU: * Chubarov, L
EM: chubarov@ict.nsc.ru
AF: Institute of Computational Technologies SB RAS, Academician Lavrentjev Ave., 6, Novosibirsk, 630090 Russian Federation
AU: Fedotova, Z
EM: zf@ict.nsc.ru
AF: Institute of Computational Technologies SB RAS, Academician Lavrentjev Ave., 6, Novosibirsk, 630090 Russian Federation
AU: Eletsky, S
EM: zf@ict.nsc.ru
AF: Novosibirsk State University, University Ave., 6, Novosibirsk, 630090 Russian Federation
AB: Recent scientific publications contain enough evidences that the key source mechanisms of formation of abnormal tsunami waves in near-shore areas of the World Ocean are the large-scale underwater landslides. The mathematical modeling of generation of waves of such nature is reduced to the description of dynamics of the motion of the drowned mass of a soil and to the solution of a hydrodynamic problem for the arising surface waves. The scales of temporal and (or) spatial characteristics of lithodynamic processes are different, therefore several approaches to simulation of the motion of a landslide were proposed. In a number of publications the landslide is treated as a non-deformable solid body. The attempts to consider a landslide as elastoplastic medium moving and interacting with the surrounding flow are made. For some underwater slides the simulation of a phenomenon is represented within the framework of a two-layer fluids of different density and viscosity. To construct the numerical model of a phenomenon it is necessary to match the mathematical models of the slide motion and surface water waves propagation. The aim of this work is to construct and to investigate the hydrodynamic component of such a complex model. It is supposed, that the phenomenon has the long-wave nature, and the simulation of surface waves in ideal incompressible fluid is conducted in a usual way - within the framework of a hierarchy of shallow water models of different order of hydrodynamic approximation (linear, non-linear and non-linear-dispersion equations). The numerical algorithms are based on finite-difference methods. For hyperbolic equations the Mac-Cormack type schemes with special adjustment of the right hand side is used. For non-linear-dispersion equations the schemes of the second order of approximation keeping a number of control parameters, permitting to allow for or to leave out the non-linear effects, and also selectively to apply a procedure of smoothing are constructed. A one dimensional numerical model of waves generated by a body moving over the bottom was constructed as a first step. The relation of parameters of a generated wave to the shape and size of a mooving body, and also from the law of is studied. We consider the cases of a horizontal and an inclined bottom. The problem was further investigated, when the landslide is modelled within the framework of elastoplastic medium. Our numerical experiments have proved that the specific features of the wave generation process can be robustly reproduced within the framework of approximated hydrodynamic models: the forerunners by the way of denivellation waves, rearrangement of wave process are described at the moment when the landslides slows down and other effects. The features of the processes, related to the non-linear and dispersive characteristics of the medium are determined. The work is executed under financial support of the Russian Foundation for Basic Researches, grant 03-05-64108, and also the Program of Integration Researches SB RAS, grant 2003-5.
DE: 4255 Numerical modeling
DE: 4564 Tsunamis and storm surges
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting