仿生撓性尾鰭BCF泳動之流場實驗分析

Abstract

中文摘要 水下載具近年來有許多學者投入研究，而仿生水下載具更是蓬勃發展，來自於其在水下具有高推進機制，兼具環保、綠能、隱密性等等。本實驗研究對象為魚體BCF泳動之流場觀察，其特點是可利用後方渦漩產生的渦漩結構使其推進力增加，具有高機動和可操作性。仿生撓性尾鰭主要在低雷諾數下進行，在此狀況下會有許多複雜現象產生，例如：反卡門渦漩。為簡化問題，本實驗以展弦比1的魚鰭拍撲，使用粒子顯影、並配合升阻力量測，討論撓性魚鰭後方渦旋發展以及結構。本實驗的工作流體為甘油和水的混合物，以雷諾數500配合，史卓赫數0.2、0.4、0.6，並進行平移運動。使用六軸力規紀錄升阻力隨時間的變化，並觀察不同史卓赫數下升阻力的變化，配合ansys模擬對比其結果。流場觀測方面，藉由釋放顯影粒子，配合PIV方法計算流場渦度場。 本文最後進行不同史卓赫數下流場升阻力配合PIV觀察，搭配力元理論做流場定量分析，在推力方面隨史卓赫數增加推力隨之增加，其中環境渦度影響最大， 側緣渦渦漩並未隨史卓赫數增加而有改變，影響渦旋結構主要為尾渦效應。

Abstract In this study, we investigate three-dimensional thrust mechanisms of finite rigid and deformable flapping plates experiment as a caudal fin of the BCF (body and/or caudal fin) swimming fish at low Reynold numbers , water propeller vehicles in recent years, many scientist involved in research, and biomimetic water propeller vehicle is popular, with a high from its water propulsion mechanism, both environmental protection, green energy, privacy and so on. The experimental study of the fish BCF swimming field observation, which is characterized by the use of the vortex structure behind it generated vortex propulsion increases with high mobility and operability. Bionic flexible caudal fin is mainly carried out at low Reynolds number, in this case there will be many complex phenomena, such as: reversed-Karman vortex. To simplify the problem, this experiment aspect ratio 1 flapping, using particle imaging, and with the lift and drag measurements. Discuss the development of flexible fin behind and vortex structures. The working fluid is a mixture of experimental glycerol and water, with Reynolds number 500, the number (St=0.2,0.4 and 0.6), and two-way movement. Using the six-axis force compliance record up resistance over time and observe up under a different number St resistance changes with ansys simulation comparison of its results. Flow field observations, with the release of the developer particles to calculate the flow field vorticity with PIV method.