孤立波於泥床上過垂直圓柱的受力實驗

Abstract

孤立波是一種廣為學者使用的非線性長水波，特點為非線性與波頻散同時存在且達到平衡使波型能穩定傳播不變形，而孤立波、圓柱和泥床三者相互作用的研究實驗的數量卻非常少數，本研究探討孤立波在黏性泥床上通過垂直圓柱時的受力特性，透過在造波水槽系統中架設一力感測器，以實驗方法來量測孤立波對於黏性泥床上垂直圓柱產生的受力，並使用開源數值模擬軟體OpenFOAM建立與實驗水槽同尺度的三維數值波浪水槽，將模擬結果與實驗結果進行比較與分析。研究結果表明，此力感測器的架設有確實量測到圓柱結構物在水下所受到的波浪水平力，且圓柱結構物無論泥床的存在與否，所受到的最大正向力一定都會大於最大反向力，當有泥床的存在時，會讓波高有較大的衰減，圓柱結構物的受力增加，且從受力歷時圖也可發現因為黏性流體的存在導致受力的最大值最慢到達。

Solitary wave is a type of nonlinear long water wave widely used by scholars, characterized by the coexistence and balance of nonlinearity and wave dispersion, allowing the wave shape to propagate stably without deformation. However, there are very few experimental studies on the interaction among solitary waves, cylinders, and mud beds. This study explores the force characteristics of a solitary wave passing through a vertical cylinder on a viscous mud bed. A force sensor is installed in a wave tank system to experimentally measure the force exerted by the solitary wave on the vertical cylinder on the viscous mud bed. Additionally, the open-source numerical simulation software OpenFOAM is used to establish a three-dimensional numerical wave tank of the same scale as the experimental tank. The simulation results are compared and analyzed with the experimental results. The study results indicate that the installation of this force sensor accurately measures the horizontal wave force on the cylindrical structure underwater. Regardless of the presence of the mud bed, the maximum positive force on the cylindrical structure is always greater than the maximum negative force. When a mud bed is present, there is greater wave height attenuation, the force on the cylindrical structure increases, and the force-time history also shows that the maximum force takes longer to reach due to the presence of the viscous fluid.