孤立波衝擊岸壁動態模擬及探討－採用光滑粒子流體動力法

本文以光滑粒子流體動力法建構一個具有波浪產生機制及可模擬波浪湧上岸衝擊壁面之數值水槽，用以探討孤立波衝擊岸壁之動態表現。不同初始Froude數下動板產生之波浪型態被仔細研究，初始Froude數大於1產生之波浪會翻湧；而初始Froude數小於1產生之波浪雖不會翻湧，但隨著初始Froude 數的增大，波峰呈現越來越尖銳。詳細探討了壁面傾角θ2=45∘、θ2=90∘及θ2=135∘三種情形受湧入水流沖擊之動態演進過程，發現造成θ2=135∘和θ2=45∘、θ2=90∘二者水流回湧時之波浪翻湧機制並不相同，θ2=135∘回湧過程之波浪翻湧，主要受重力產生離開壁面加速度所主導，而θ2=45∘、θ2=90∘回湧過程之波浪翻湧，主要是在動、位能互換下，沿壁面產生動量相反兩股水流互相衝擊所造成。

關鍵字

光滑粒子流體動力法；孤立波；波浪翻轉；衝擊

並列摘要

Numerical water tank, which has the abilities to generate solitary wave and simulate the dynamic evolution of waves impacting costal wall, was constructed by smoothed particle hydrodynamics method. Wave shapes, which are generated by moving plate at various initial Froude number, were carefully studied. As initial Froude number is above 1, wave splash-up appears. As initial Froude number is below 1, no wave splash-up is observed, but sharper wave crest accompanies with the increase of initial Froude number. Dynamic evolutions of flows introduced by the inundation of solitary wave which impacts solid walls with various inclined angles θ2 are carefully investigated. Definitely different mechanisms driving the wave splash-down along solid wall between the case with θ2 = 135°and the cases with θ2= 45° and θ2= 90° are found. As the inclined angle of solid wall is at θ2= 135°, gravity force introduces off-wall accelerations to flow particles along inclined wall; the off-wall accelerations make flow particles to splash-down. As the inclined angle of solid walls is at θ2= 45° or θ2= 90°, flow particles splashing-down along inclined wall is mainly introduced by the impacting of two streams with opposite momentum. And, the appearance of two streams with opposite momentum is dominantly caused by the exchanges of potential and kinetic energies of flow particles.

並列關鍵字

Smoothed particle hydrodynamics ； Solitary wave ； Wave splash-up ； Impact

國際替代計量

孤立波衝擊岸壁動態模擬及探討－採用光滑粒子流體動力法

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