Laboratory Effects in Beach Studies. Volume VI. Movable-Bed Experiments With H (Sub o)/L(sub o) = 0.004.
COASTAL ENGINEERING RESEARCH CENTER FORT BELVOIR VA
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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 antinode 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.
- Physical and Dynamic Oceanography