Haas Kevin A.

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Haas
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Kevin A.
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  • Article
    A wetting and drying scheme for ROMS
    (Elsevier B.V., 2013-05-24) Warner, John C. ; Defne, Zafer ; Haas, Kevin A. ; Arango, Hernan G.
    The processes of wetting and drying have many important physical and biological impacts on shallow water systems. Inundation and dewatering effects on coastal mud flats and beaches occur on various time scales ranging from storm surge, periodic rise and fall of the tide, to infragravity wave motions. To correctly simulate these physical processes with a numerical model requires the capability of the computational cells to become inundated and dewatered. In this paper, we describe a method for wetting and drying based on an approach consistent with a cell-face blocking algorithm. The method allows water to always flow into any cell, but prevents outflow from a cell when the total depth in that cell is less than a user defined critical value. We describe the method, the implementation into the three-dimensional Regional Oceanographic Modeling System (ROMS), and exhibit the new capability under three scenarios: an analytical expression for shallow water flows, a dam break test case, and a realistic application to part of a wetland area along the Georgia Coast, USA.
  • Preprint
    Tidal stream energy site assessment via three-dimensional model and measurements
    ( 2012-08-12) Work, Paul A. ; Haas, Kevin A. ; Defne, Zafer ; Gay, Thomas
    A methodology for assessment of the potential impacts of extraction of energy associated with astronomical tides is described and applied to a site on the Beaufort River in coastal South Carolina, U.S.A. Despite its name, the site features negligible freshwater inputs; like many in the region, it is a tidal estuary that resembles a river. A three-dimensional, numerical, hydrodynamic model was applied for a period exceeding a lunar month, allowing quantification of harmonic constituents of water level and velocity, and comparison to values derived from measurements, recorded at a location within the model domain. The measurement campaign included surveys of bathymetry and velocity fields during ebb and flood portions of a tidal cycle for model validation. Potential far-field impacts of a generic tidal energy conversion device were simulated by introducing an additional drag force in the model to enhance dissipation, resulting in 10-60% dissipation of the pre-existing kinetic power within a flow cross-section. The model reveals e ffects of the dissipation on water levels and velocities in adjacent areas, which are relatively small even at the 60% dissipation level. A method is presented to estimate the optimal vertical location for the energy conversion device and the potential power sacrificed by moving to a di fferent altitude.