Topographical Scattering of Waves: Spectral Approach

The topographical scattering of gravity waves is investigated using a spectral energy balance equation that accounts for first-order wave-bottom Bragg scattering. This model represents the bottom topography and surface waves with spectra, and evaluates a Bragg scattering source term that is theoretically valid for small bottom and surface slopes and slowly varying spectral properties. The robustness of the model is tested for a variety of topographies uniform along one horizontal dimension including nearly sinusoidal, linear ramp, and step profiles. Results are compared with reflections computed using an accurate method that applies integral matching along vertical boundaries of a series of steps. For small bottom amplitudes, the source term representation yields accurate reflection estimates even for a localized scatterer. This result is proved for small bottom amplitudes h relative to the mean water depth H. Wave reflection by small amplitude bottom topography thus depends primarily on the bottom elevation variance at the Bragg resonance scales, and is insensitive to the detailed shape of the bottom profile. Relative errors in the energy reflection coefficient are found to be typically 2h/H.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/0733950X
• Authors:
  • Magne, R
  • Ardhuin, F
  • Rey, V
  • Herbers, THC
• Publication Date: 2005-11

Language

• English

Media Info

• Media Type: Print
• Features: Appendices; Figures; References;
• Pagination: pp 311-320
• Serial:
  • Journal of Waterway, Port, Coastal and Ocean Engineering
  • Volume: 131
  • Issue Number: 6
  • Publisher: American Society of Civil Engineers
  • ISSN: 0733-950X
  • EISSN: 1943-5460
  • Serial URL: http://ascelibrary.org/journal/jwped5

Subject/Index Terms

• TRT Terms: Equations; Gravity waves; Mathematical models; Spectrum analysis; Topography
• Uncontrolled Terms: Wave reflection; Wave scattering
• Subject Areas: Administration and Management; Marine Transportation;

Filing Info

• Accession Number: 01007066
• Record Type: Publication
• Files: TRIS
• Created Date: Nov 7 2005 4:42PM