| 摘要 |
PURPOSE:To enable the measurement of an zone of the coast from the seabed surface to the water surface, by a construction wherein the central part of a slender box is partitioned by a partition wall into two sand storing boxes, a space above the boxes is surrounded in the shape of a box by a net having meshes not allowing drift sand to pass, and an opening is provided in the opposite ends. CONSTITUTION:An opening is provided toward the direction 22 of waves on a seabed surface 21, and partition plates 8 and 9 are lifted, so as to fix click 16 to a metal stopper 17. When the front end 23 of the crest of a wave comes to the opening of a sand catching element 3, a door 6 opening inward is made to open by the speed of a wave motion, and the drift sand flows into the sand catching element 3 therethrough. Since the sand catching element 3 is surrounded by a net, a fluid passes therethrough, while the sand is deposited in a sand storing box 1. A door 9 opening inward is closed in the meantime, and therefore the drift sand does not flow into a sand catching element 4. When the front end 24 of the trough of the wave comes to the opening of the sand catching element 4, the direction of the flow speed turns to be reverse to the direction of advance of the wave, a door opens while the door 6 closes, and the drift sand flowing to the right is deposited in a sand storing box 2. At the time of completion of measurement, the partition plates 8 and 9 are closed, an apparatus is lifted, and the volume of the sand in each of the sand storing boxes 1 and 2 is determined. Thereby, the entire flow rate of the drift sand passing through the openings and the direction of movement thereof can be calculated.
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