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Title: Influence of domain size and grid structure on the response characteristics of a hurricane storm surge model
Authors: Blain, Cheryl Ann
Westerink, Joannes J.
Luettich, Richard A. (Richard Albert), 1957-
Scheffner, Norman W.
Keywords: Circulation model
Finite element model
Finite element method
Computational domain size
Grid analysis
Computational grid resolution
Hydrodynamic model
Storm surges--Models
Tropical storm simulation
Two-dimensional model
Ocean waves
Numerical grid generation
Dredging Research Program (U.S.)
Publisher: U.S. Army Engineer Waterways Experiment Station
Series/Report no.: Technical Report (Dredging Research Program (U.S.)) ; no.Technical Report DRP-95-4
Abstract: Formulation of a numerical storm surge model directly affects the physical content of the predicted storm surge response. The influence of domain size and grid structure on computations of storm surge generation in the coastal region are studied. Storm surge response along the Florida shelf in the Gulf of Mexico due to Hurricane Kate is examined over three domains using two different open ocean boundary forcing functions. The computed storm surge response indicates that a small domain situated primarily on the continental shelf is inadequate since cross shelf boundaries are in regions of significant storm surge generation where surge and therefore boundary conditions are not known a priori. A second domain including the entire Gulf of Mexico basin captures the primary storm surge well but may not correctly model resonant modes. The dependence of these modes on interactions with contiguous basins makes accurate setup by the boundary condition specification difficult. The primary storm surge response as well as resonant modes excited by the storm are best represented using the largest domain, which encompasses the western North Atlantic ocean, the Caribbean Sea, and the Gulf of Mexico. This domain with deep Atlantic ocean boundaries facilitates simple boundary condition specification and minimizes the influence of boundary conditions on storm surge generation in the coastal region. Basin resonant modes and basin interactions are also captured. Comparisons between storm surge elevations computed over fourteen grid discretizations subject to four synthetic hurricane forcings indicate that accurate predictions of storm surge result when significant refinement of shoreline geometry and nearshore regions is provided along with resolution to one half the spatial scale of the storm over deep waters. These grid discretization requirements are best met using a graded grid structure which yields low unifonn prediction errors throughout the domain and minimizes computational effort. Application of the guidelines for specification of domain size and grid structure to Hurricanes Kate and Camille reinforces the necessity of using a large domain, which has high levels of resolution in nearshore regions and areas of complex coastal geometry, for accurate prediction of primary storm surge.
Description: Technical Report
Gov't Doc #: Technical Report DRP-95-4
Rights: Approved for public release; distribution is unlimited
Appears in Collections:Technical Report

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