HR: 11:50h
AN: OS42B-03    [Abstracts]
TI: Wet and Dry Algorithms for Modeling Hydrodynamics in Bays/Estuary/Coastal Areas
AU: * Shan, H
EM: hshan@uta.edu
AF: University of Texas at Arlington, Department of Mathematics University of Texas at Arlington, Arlington, TX 76019, United States
AU: Yeh, G
EM: gyeh@mail.ucf.edu
AF: University of Central Florida, Room 442B/C, ENG II, UCF 4000 Central Florida Blvd, Orlando, FL 32816, United States
AB: To adequately address inundation problems in hydrodynamic modeling over bays/estuaries/coastal areas, appropriate wet and dry algorithms hold the key to accurately capture the moving fronts of waters over land surfaces. From the point of view of computational methods, two approaches are available, namely the moving grid method and the fixed-grid approach. The moving grid method usually adopts either the Lagrangian or the arbitrary Lagrangian-Eulerian (ALE) representation. In the Lagrangian representation, the grid movement strictly follows the local velocity of the fluid. Therefore the grid may deform severely for complex flows involving circulations and vortices. In the ALE representation, arbitrary velocity can be assigned to node movement, thus the grid movement in the interior of the domain is independent of the flow velocity. Thus, it is possible for the ALE method to maintain reasonably shaped meshes and describe the moving fronts accurately at the same time. In the fixed-grid method, the grid used to solve the flow problem is entirely or quasi-entirely fixed and the equations are expressed using the Eulerian representation. The moving fronts are identified based on whether computational cells are wet or dry. Dry cells are either taken out of the computational domain or assigned a minimum depth and remained in the computational domain. A dry cell, if it has been taken out of the domain, can become wet again if its neighboring cells are wet. There may be severe mass conservation errors if the scheme of maintaining a minimum depth is employed. In this paper, we present the moving grid method used in the modeling of the three dimensional surface flow in large water bodies surrounded by mash flats. Three algorithms were developed to model inundation of surrounding land surfaces: (1) semi-Lagrangian moving grid, (2) hybrid scheme of storage and hydrodynamic cells, and (3) coupled scheme of three-dimensional and two- dimensional flows. These algorithms are demonstrated and their advantages and disadvantage are discussed. The inundation of the Loxahatchee Estuary over its flood plain is used to demonstrate the robustness of the coupled scheme of 3D and 2D flows.
UR: http://people.cecs.ucf.edu/yeh
DE: 1805 Computational hydrology
DE: 1847 Modeling
DE: 4217 Coastal processes
DE: 4235 Estuarine processes (0442)
DE: 4534 Hydrodynamic modeling
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting