本研究以計算流體力學 (Computational Fluid Dynamics, CFD) 方法進行模擬，著重於離岸風機基樁和雙頻波交互作用之水動力探討。數值模擬方面，將以有限體積法 (Finite Volume Method, FVM) 做為離散求解工具；波浪之自由液面處理方面，將以體積分率 (Volume of Fraction, VOF) 方法處理水與空氣之兩相流問題；風機基樁受波浪作用下之黏性流問題，將以RANS方程式搭配RNG k-ε紊流模型 (RNG k-ε turbulent model) 求解基樁受水動力作用時的情形，並使用邊界層網格設定 (inflation)，生成細長六面體網格於基樁周圍之邊界層進行網格細化處理，藉以計算邊界層內之黏性流域對基樁之影響；在消波方面，採用數值消波設定 (numerical beach)，使波浪於通過基樁後進行消散。此外，本文將探討不同型式基樁在不同頻率差情況下之最大與最小溯升高度位置，將以無因次化調變頻率δ ̂分析基樁周圍之溯升情形，最後探討雙頻波所造成之受力影響。
由模擬結果得知，單樁式、重力式、三角管式和套管式基樁相較之下，週期差對單樁式、重力式、三角管式基樁之衝擊係數影響較大，反觀套管式基樁，週期差之影響則是較小。

The purpose of the present study was to discuss the wave run-up heights and wave impact forces induced by nonlinear wave groups. The Finite Volume Method (FVM) is a discretization technique for solving partial differential equations implemented in Computational Fluid Dynamics (CFD). The Volume of Fraction (VOF) method is suggested as a free surface modeling technique to track and locate free surfaces. The hydrodynamic simulation of the wave-structure interaction was conducted using a Reynolds-averaged Navier-Stokes (RANS) solver for incompressible fluid flows and employing an Re-Normalization Group (RNG) k-ε turbulent closure. In order to solve the viscous flow around the foundation regions, an inflation scheme was used to generate the smaller hexahedral meshes and refine them. To avoid wave reflection, numerical beach treatment was employed. Furthermore, the maximum and minimum wave run-up heights around the foundations for different wave steepness are analyzed by the normalized parameter of frequency modulation δ ̂. Finally, the wave impact force is also discussed and summarized qualitatively and quantitatively.
By means of our CFD model, it’s obviously found that for the jacket foundation period difference did not have a great influence on the value of slamming coefficient in comparison with the monopile, gravity-based and tripod foundations.

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