Accession Number : ADA561812


Title :   Wave Reflection on a Two-Slope Steep Beach


Descriptive Note : Master's thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA


Personal Author(s) : Watson, David H


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA561812


Report Date : Mar 2012


Pagination or Media Count : 49


Abstract : Wave reflection of sea-swell (0.05-0.20 Hz) energy on a two-slope (1/7.6 nearshore and 1/19 offshore) steep beach with no subaqueous sandbar is studied. The dataset were collected using a cross-shore array of 4 Acoustic Doppler Current Profilers measuring velocity and pressure at 1 Hz continuously for 40 days. Measurement of pressure and velocity at the same location allows data to be decomposed into onshore and offshore components to determine reflection. The long data set captured a wide range of wave conditions at various tidal stages. Observations show low amplitude long period waves produced energy reflection coefficients up to 80%, with most in the 30-50% range. There was a measured increase in the number of nodes and anti-nodes at higher frequencies and observations farther offshore consistent with theory. Field data were compared to an analytical two-slope model that predicts the crossshore nodal structure of standing waves. The predicted locations of nodes and anti-nodes are in good agreement with observations.


Descriptors :   *BEACHES , *WAVES , DATA BASES , ENERGY , INSHORE AREAS , OFFSHORE , REFLECTION , SHORES , SLOPE , TIDES


Subject Categories : Atmospheric Physics
      Physical and Dynamic Oceanography


Distribution Statement : APPROVED FOR PUBLIC RELEASE