Accession Number : ADA455449


Title :   Longshore Sediment Transport Rate Calculated Incorporating Wave Orbital Velocity Fluctuations


Descriptive Note : Final rept.


Corporate Author : ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB


Personal Author(s) : Smith, Ernest R.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA455449


Report Date : SEP 2006


Pagination or Media Count : 233


Abstract : Laboratory experiments were performed to study and improve longshore sediment transport rate predictions. Measured total longshore transport in the laboratory was approximately three times greater for plunging breakers than spilling breakers. Three distinct zones of longshore transport were observed across the surf zone: incipient breaker zone, inner surf zone, and swash zone. Transport at incipient breaking was influenced by breaker type; inner surf zone transport was dominated by wave height, independent of wave period; and swash zone transport was dependent on wave period. Selected predictive formulas to compute total load and distributed load transport were compared to laboratory and field data. Equations by Kamphuis (1991) and Madsen et al. (2003) gave consistent total sediment transport estimates for both laboratory and field data. Additionally, the CERC formula predicted measurements well if calibrated and applied to similar breaker types. Each of the distributed load models had shortcomings. The energetics model of Bodge and Dean (1987) was sensitive to fluctuations in energy dissipation and often predicted transport peaks that were not present in the data. The Watanabe (1992) equation, based on time-averaged bottom stress, predicted no transport at most laboratory locations. The Van Rijn (1993) model was comprehensive and required hydrodynamic, bedform, and sediment data. The model estimated the laboratory cross-shore distribution well, but greatly overestimated field transport.


Descriptors :   *VELOCITY , *ORBITS , *SEDIMENT TRANSPORT , *WAVES , STRESSES , POSITION(LOCATION) , LABORATORY TESTS , MODELS , MEAN , ENERGETIC PROPERTIES , SURF , SHORES , BOTTOM , EQUATIONS , DISTRIBUTION , ENERGY , RATES , DISSIPATION , SENSITIVITY , ESTIMATES


Subject Categories : CELESTIAL MECHANICS
      PHYSICAL AND DYNAMIC OCEANOGRAPHY
      FLUID MECHANICS


Distribution Statement : APPROVED FOR PUBLIC RELEASE