本文以非線性演進型緩坡方程式為控制方程式，並利用有限差分法 (Finite Difference Method, FDM)，建立一維數值模式，以模擬波浪變形效應。文中將緩坡方程式推導至二階量，以改進無法計算非線性波浪之限制。本文模式計算等水深地形底床時，與Stokes 波比較，發現可準確地模擬波浪變形；並應用於波浪通過潛堤地形底床，發現在潛堤前方與上方的結果與實驗數據比較，有良好的結果，在潛堤後方，由於非線性效應的增強，導致所得結果與實驗數據比較，並非相當地吻合，但就趨勢而言，還是有良好的一致性。

The nonlinear mild slope equation was discretized by a finite difference method to simulate wave transformations. In this paper, the mild slope equation is expended to the second-order approximation for improving the limitation of calculating nonlinear waves. The numerical model is applied to a set of published experimental cases. Comparison of the results shows that the present model adequately predicts the measurements.

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