浸沒邊界法在二維淺水波流場模擬之應用探討

Abstract

本研究在一既已發展之水深平均二維淺水波模式中，植入浸沒邊界法(Immersed Boundary Method)處理內部邊界問題，用以模擬流場內部具非浸沒式水工構造物(橋墩、丁壩)的案例。本研究探討浸沒邊界法中2點、4點狄拉克脈衝函數(Dirac Delta Function)於淺水波模擬應用之適用性，並分析內部邊界標記點(IB markers)於格點佈置之關係性。模式之應用測試主要乃選取流場中具橋墩、丁壩的定床及動床實驗案例進行模擬，除比對流場之正確性外，並就局部沖淤的相對位置及刷深深度之比較結果，說明模式之限制條件。

The present study embeds the Immersed Boundary Method (IB method) in the 2D depth-averaged shallow water flow model being developed to solve the interior boundary problem in open channel. Two point and four point Dirac delta functions used in IB method were studied to examine their suitable equation. In addition, the effect caused by various ratios of IB marker’s gap to grid size were also analyzed. Two experimental cases, including cylinder pier and spur dike, were studied herein to demonstrate the practical applicability and limitation of IB method in fixed-bed and movable-bed open channel flow simulation.