Please use this identifier to cite or link to this item: https://hdl.handle.net/11681/5143
Title: Laboratory effects in beach studies, volume 6: movable-bed experiments with Ho/Lo = 0.004
Authors: Chesnutt, Charles B.
Stafford, Robert P.
Keywords: Breakers
Coastal Engineering
Currents
Model Studies
Movable-Bed Experiments
Wave Envelopes
Wave Generators
Wave Height Variability
Wave Reflection
Wave Tanks
Issue Date: Mar-1978
Publisher: Coastal Engineering Research Center (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Miscellaneous report (Coastal Engineering Research Center (U.S.)) ; no. 77-7 v. 6.
Description: Miscellaneous Report
Abstract: Two experiments with long low waves on 0.2-millimeter sand slopes in tanks 6 and 10 feet wide showed very different profile development, apparently because current circulation, present only in the 6-foot tank, was more effective in distributing sand in the onshore-offshore direction. In the 6-foot tank, the profile developed a more distinct shelf separated by two relatively steep seaward-facing slopes. The clockwise circulation pattern occurred over the shelf between the foreshore and the first seaward anti node of the standing wave envelope, a distance approximately twice the tank width. This current pattern in the 6-foot tank began to disintegrate after about 70 hours. The profile in the 6-foot tank was still changing at 135 hours when the experiment ended; in the 10-foot tank, the profile had reached approximate equilibrium after 25 hours. In the 6-foot tank, the foreshore eroded throughout the test, but in the 10-foot tank it quickly stabilized. In the 6-foot tank, the offshore consisted of an almost flat shelf and a steep seaward slope as long as the circulation prevailed, but became more gently sloping after the circulation disappeared. In the 10-foot tank, the offshore was less steep and stabilized after about 50 hours. Reflection coefficient, KR varied from 0.17 to 0.31 in the 6-foot tank, increaslng as the shelf developed during the time of active circulation. KR then began decreasing as the steep offshore slope began flattening. In the 10-foot tank, KR was higher, varying from 0.24 to 0.37 and tended to increase with steepening of the foreshore. Note: Reflection coefficient KR is not accurately represented in this online abstract due to the character set limitations of this system. The coefficient will be accurately presented in the downloaded pdf.
URI: http://hdl.handle.net/11681/5143
Appears in Collections:Miscellaneous Report

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