An analysis of the sediment concentration around the offshore submerged breakwater

• Main Authors: Shang-Yi Lai, 賴尚儀
• Other Authors: I-Chen Lin
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/99060179301090034146

碩士 === 淡江大學 === 水資源及環境工程學系 === 89 === In this study, the flow visualization technique is utilized to obtain the changes and distribution of the sediment concentration around offshore submerged breakwater. In conditions of the same wave height with different wave periods (T),we analyzed the sediment concentration on the horizontal and sloping(1/30) beaches. This study consist of different distances and moments. The analyses consist of three parts:(1) The changes of the sediment concentration,(2) The relation between the water depth and the average concentration, (3) The changes of total concentration in the back and front of the offshore submerged breakwater. The results had the same trendency as those in the previous studies, so the flow visualization technique is an effective tool in the study of sediment concentration. The results showed, when the wave period is long, the offshore submerged breakwater had better effects on the beach stability. As the width(B) of the offshore submerged breakwater on the sloping(1/30) beach, the ratio(R) of the height of the offshore submerged breakwater and water depth on the horizontal beach increased, the beach profile shows better stability. When the reflection coefficient is large the sediment concentration in the front of the offshore submerged breakwater is also large. As the experiments continued longer than 30 minutes, the changes of beach profile is little and the beach became stable. When wave period is long, there is a direct relation between the sediment concentration and water depth, the sediment concentration increased as the water depth decreased.