串列式雙振動翼助推器設計改良之研究

Abstract

本研究主要目的是為了開發不干擾水下滑翔機滑翔，且能協助水平前進之助推器。先前本研究室曾提出串列式雙振動翼之設計，並進行了水動力數值模擬及實體模型的水槽實驗。研究結果顯示原設計之串列式雙振動翼之推進性能不如預期，仍有改善空間。但另一方面也確認了使用CFD軟體 ” FLUENT ” 所發展的串列式雙振動翼助推器之流體動力數值計算工具有相當的可靠性。因此，延續之前的成果，本研究持續運用該計算工具，在非穩態流場條件下，以動態網格進行多種振動翼型式助推器之流體動力分析，進一步提出串列式雙振動翼之改良設計，探討雙振動翼之配置，各振動翼振幅、相位、頻率、前後翼間距等參數對於推進性能之效應，並釐清了前翼提升雙振動翼推進效率力之力學機制。 本研究藉由數值計算分析探討所獲得的結果，將能作為後續修正實體模型，進行水槽試驗之規劃依據，最終將求促成兼具水平移動能力的水下滑翔機的實現。

In view of the fact that an underwater glider is lack of horizontal mobility, a concept of booster with two oscillating fins in series was proposed and investigated in the previous study to enhance the horizontal mobility without disturbing gliding. A test apparatus was established and a series of tank tests were carried out for clarifying its hydrodynamic characteristics. However, it was found that the propulsion performance of the proposed design is not as good as expected, and some modification may be needed for improving the performance. In addition, the CFD software “FLUENT” was applied for comparison, and its validity as a tool to evaluate the design has also been confirmed. In the present study, a modified design is proposed and its performance is investigated using the numerical simulation. It’s also confirmed that the efficiency of two oscillating fins in series can be improved by the fore fin with proper phase lead.