[[alternative]]An Analysis of the Sediment Concentration around the Offshore Submerged Breakwater

[[abstract]]本文主要目的是在利用流場可視化過程之影像處理，以分析在同一波高不同波浪週期條件下，在水平與1/30坡度的沙灘上，懸浮質濃度在不同佈置離岸潛堤附近之變化與分布，藉以探討離岸潛堤對堤後之定沙效果。分析的方法分為不同瞬間與不同距離；針對以下作探討:(1)懸浮質濃度在不同水深下之變化。(2)平均懸浮質濃度與水深之關係。(3)累積總濃度在堤前與堤後之變化。分析結果顯示，在坡度或水平動床中，在長週期波時離岸潛堤均有較好的削減波能及堤後定沙效果。而坡度動床中堤寬的增加對堤後定沙效果較佳，水平動床中則是以堤深的增加有較佳的定沙效果。反射率與懸浮質濃度變化有對應關係，當反射率較高者在堤前的漂沙活動較頻繁。[[abstract]]In this study, the flow visualization technique is utilized to obtainthe changes and distribution of the sediment concentration aroundoffshore submerged breakwater. In conditions of the same wave heightwith different wave periods(T), we analyzed the sediment concentrationon the horizontal and sloping(1/30) beaches. The analyses consist ofthree parts: (1) The changes of the sediment concentration, (2) Therelation between the water depth and the average of concentration, (3)The changes of total concentration in the back and front of theoffshore submerged breakwater. The results showed, when the waveperiod is long, the offshore submerged breakwater had better effectson the beach stability. As the width(B) of the offshore submergedbreakwater on the sloping beach, the ratio(R) of the height of theoffshore submerged breakwater and water depth on the horizontal seabedincreased, the beach profile shows better stability. When thereflection coefficient is large the sediment concentration in thefront of the offshore submerged breakwater is also large.[[sponsorship]]成功大學水工試驗所; 台灣海洋工程學會[[notice]]補正完畢[[conferencetype]]國內[[conferencedate]]20011213~20011213[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺南, 臺