水力緩衝區銜接方法在河口水動力計算之應用

Hydraulic Buffer Zone Techniques for Estuarine Hydrodynamic Modeling

林孟郁(Meng-Yu Lin) ； 洪政暘(Cheng-Yang Hung) ； 張正緯(Cheng-Wei Chang) ； 黃良雄(Liang-Hsiung Huang)

《中國土木水利工程學刊》 25卷2期 (2013/06) Pp. 161-170

https://doi.org/10.6652/JoCICHE.201306_25(2).0007

摘要

本研究提出水力緩衝區的概念，將其應用於河口水動力計算模式分區演算的銜接，以解決在地形劇烈變化處易產生的數值不穩定。水力緩衝區係設置於地形劇烈變化處，其內的流場並不直接計算，而是以滿足質量守恆來銜接分區，並利用克利金法作為內插工具，經過反覆疊代的過程直到邊界值滿足收斂條件為止。此方法亦可應用於分區空間尺度差異過大之銜接。為探討水力緩衝區銜接方式的可行性，本研究設計垂直地形不連續、緩坡地形、陡坡地形，以及迴水演算等案例，以進行水力緩衝區在單連通區域、複連通區域和斜向緩衝區的測試。設計地形之測試均呈現合理的模擬結果。而後應用於現地花蓮美崙溪河口之河海相接的案例模擬，演算結果顯示水力緩衝區銜接方法，能拓展近岸波潮流及河口水動力演算模式之應用範圍。

關鍵字

水力緩衝區 ； 單連通 ； 複連通 ； 河口水動力模擬 ； 克利金法

並列摘要

In this work, a numerical treatment using ”hydraulic buffer zone” is proposed to connect computational subregions in the numerical modeling of flows in oceans, estuaries and rivers. This method may avoid computational difficulties due to abrupt changes in terrain. Hydraulic buffer zone is set to be located at the area with abrupt changes in terrain, and decomposes the computational domain into two subregions. Direct simulation of the flow in a hydraulic buffer zone is ignored, and the connection of the subregions is performed by using the condition of mass conservation. Kriging method is employed to interpolate/extrapolate the free-surface elevation across a hydraulic buffer zone. The iterative computations across the buffer zone are performed until the results of two successive iterations converge at every time step. Hydraulic buffer zone also can be applied to the connection of two computational regions with different spatial resolutions. Several terrains with simply-connected and multiply-connected subregions are employed to test the capability of this method. Finally, this method is applied in the hydrodynamic modeling of the estuary of the Mei-Luan Creek in HuaLien City. Numerical results show that the treatment of hydraulic buffer zone may extend the capability of nearshore and estuarine hydrodynamic modeling.

並列關鍵字

hydraulic buffer zone ； simply-connected ； multipleconnected ； estuarine hydrodynamic modeling ； Kriging method