仿生型水下載具於開闊空間以及沿邊界游動 之周圍二維壓力場數值模擬

Abstract

魚類身體兩側佈有側線系統以感測流場的變化，藉此神經組織可使魚類達成避障、追餌等效果。本研究比較利用勢流理論所計算的偶極源與數值模擬二維仿生型自主式水下載具的壓力場。論文中討論兩種壓力測量方式：針對身體周圍之壓力峰值以及方均根值，比較這兩種不同的壓力測量方法以方便未來設計控制器使用。本文之主要結果發現魚游泳時在尾鰭附近的峰對峰壓力變化最相似於偶極源。利用勢流理論推導偶極源之壓力場，其模擬結果在以下情況：魚在不同速度、魚靠牆游的距離，以及兩隻魚在平行游動時的壓力變化，其壓力表現皆與相對應的偶極源有相似的現象。根據本文所得之偶極源模式，預期在未來可運用於仿生型水下載具之控制、辨識與追蹤系統之設計。

The pressure field of dipoles caluculated by potential flow theory and that of fish swimming simulated by computational fluid dynamics are compared in this research. Numerical simulations of self-propelled swimming of a two dimensional biomimetic autonomous underwater vehicle (BAUV) in a viscous flow are investigated. The pressure around the vehicle is focused in order to obtain pressure data of artificial lateral line for the BAUV. Two measuring methods are simulated in this work, root mean square value and peak to peak value. The pressure fields of fish swim in different velocity are calculated. The results of the simulation show that the peak to peak pressure value at the tail fin of the fish has the most similarity to the dipole calculated by potential flow. Fish swim in various velocities in open field and along a solid boundary are compared to that derived using the dipole. The pressure field of a dipole is derived in closed form, and can be easily calculated. This work has demonstrated that the pattern of the pressure which is generated by the fish is similar to a dipole. The dipole field can be used for localization, detection and tracking system design of a BAUV for further research.