在河道中設置橡皮壩(Rubber dam)攔河堰來抬高水位，因為較傳統的水泥攔河堰施工簡易，許多國家的小型河川已廣為使用橡皮壩做為取水、灌溉、防洪及防治河床沖刷、海水倒灌之用，且可藉由壩頂部的水深計算流量。但洪水來臨時，橡皮壩便會受到洪水的沖擊，因此必須對橡皮壩所受的水流沖擊力和流場有深入地瞭解，以避免橡皮壩之損壞。本計畫預備採用大渦流模式與流體體積分率法計算圓柱形橡皮壩上、下游的流況和壩體的受力，模擬結果預備與水槽實驗量測得之自由水面及表面壓力比較，以驗證大渦流模式的正確性。然後再利用數值模式進行一系列的模擬，檢視福祿數、上下游水深比等參數對圓柱形橡皮壩的阻力、升力係數與流量係數之影響。本計畫之研究成果將可應用在圓柱形橡皮壩之設計與流量量測。 ;Rubber dams are frequently used around the world for irrigation, water supply, flood control, and scouring protection. The water depth above the circular-crest weir also can be used to measure the flow rate through the weir. This study plans to incorporate a Large Eddy Simulation (LES) model and the Volume of Fluid (VOF) method to investigate the interaction between the free-surface flows and a circular rubber dam. The simulation results will be compared with the results of flume experiments. The numerical model will be utilized to investigate the influences of Froude number, depth ratio on the forces and discharge coefficients of the circular rubber dams. The research results can be used to improve the design of rubber dams.
