Correlating Seabed Drifter Weights to Sand Threshold Conditions in Wave and Wave/Current Environments.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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The purpose of this study was to investigate the response of seabed drifters SBD s to combined waves and currents and, specifically, to examine the feasibility of modifying these bottom current drogues to behave more like sediment particles. This is the only known full-scale, quantitative study of the response of SBDs to wave and current forces. Standard design SEDs were modified by changing the attached weight so that the SBDs would move on the seafloor only when the flow conditions were sufficiently vigorous to initiate sediment motion. Relative drag and inertia coefficients for SBDs were evaluated and related to the Reynolds numbers and the Keulegan-Carpenter parameter. Using these relationships, a methodology was derived for selecting threshold SED weightings appropriate for different situations. The SBDs used in these tests were identical to those used in recently reported studies conducted by the U.S. Army Corps of Engineers at Duck, NC, Sand Island, AL, and Humboldt, CA.
- Physical and Dynamic Oceanography