三維非結構性網格河口模式在高雄港水動力模擬的開發與應用

Abstract

本研究為使用SUNTANS(Fringer et al., 2006)來模擬高雄港的水動力模式，SUNTANS為三維的水動力模式，在非結構性網格上解出布氏假設(Boussinesq approximation)下的Navier-Stoke方程式，水平面所使用的網格為三角形網格，垂直面則為四邊形網格，三角形的網格對於實際地形比較能夠吻合，但是對於網格的品質要求較高(要盡量接近正三角形)。而本研究則是利用SMS(Surface-water Modeling System)在高雄港的地形資料上畫出三角形網格並且內插出每個三角形頂點的座標及深度，再將輸出的網格資料轉檔成SUNTANS能使用的檔案，再藉由設定四種不同的邊界條件來驗證網格品質以及邊界條件是否能讓計算穩定，並且討論這四種邊界條件設定模擬結果的差異以及造成計算不穩的原因。我們將此邊界條件設定用來模擬高雄港的潮汐變化並與高雄潮位站(1486)觀測資料比對，並討論流場的分布來探討邊界條件設定是否合理。最後我們將開發一套高解析度三維的模式來預測颱風暴潮對於高雄港的影響以及提供對於陸地上的溢淹模式提供適當的邊界條件。

關鍵字: 颱風暴潮、SUNTANS、非結構性網格、高雄港、三維數值模式

In this thesis we used SUNTANS(Fringer et al., 2006) to simulate hydrodynamics at the Kaohsiung harbor. SUNTANS is a three-dimensional, nonhydrostatic model which solves the Navier-Stoke equations with the Boussinesq approximation on the unstructured, z-level grid. We used SMS(Surface-water Modeling System) to generate the unstructured grid for the Kaohsiung harbor and transformed the grid data to the format that can be used in SUNTANS. We used four different boundary conditions to evaluate the grid quality, and computation stability. The simulation was compared with the tidal data that was observed at the Kaohsiung tidal station. Then we discussed the relation between the flow field and the surface height caused by different boundary conditions. The ultimate goal is to develop a high-resolution 3D model to predict the influence of the storm surge to the Kaohsiung harbor as well as to provide proper boundary conditions to the inundation model for inland areas. Key words: storm surge, SUNTANS, nunstructured-grid, Kaohsiungharbor, three- dimensional numerical model.