此研究為一震波管中的氣體動力學影響的研究，主要聚焦於震波衰減的現象。對使用雙隔膜配置的成功大學震波管中存在的震波衰減現象進行了研究。研究旨在了解雙隔膜機制對震波衰減的影響，並評估不同原因造成的震波衰減的程度與其物理機制。使用商用軟體Ansys Fluent求解了二維與三維Navier-Stoke多物種方程式並獲得了數值解。分別對無黏性流動、黏性流動、雙隔膜模式的黏性流動與帶有有顯隔膜開啟時間的雙隔膜模式的震波管流動進行分析。結果顯示隨著隔膜面積減少，震波馬赫數與介面馬赫數隨之降低。同時隨著隔膜開啟時間的增加，震波馬赫數也有減少的趨勢。記錄了經過膈膜的質量流率，結果顯示質量流率與面積比呈線性關係。且隨著面積比下降，介面後氣體產生了降壓的現象。根據研究結果，對於面積比誘導震波衰減的原因可解釋為驅動氣體的膨脹。
發展了一種相對簡易的用於測量隔膜開啟時間的方法，結果顯示第二隔膜的開啟時間約於0.5毫秒至1毫秒。最後，解釋了雙隔膜模式導致震波衰減的原因是由於更小的開口面積所致。

This is a numerical and experimental study of shock tubes internal dynamics, with special emphasis on the phenomenon of shock speed reduction, often referred to as shock attenuation. This phenomenon was observed in the National Cheng Kung University (NCKU) shock tube, thus this work aims at isolating the main causes behind shock attenuation. The tube employs a series of two diaphragms to tune the pressure ratio and separate the driver from the driven tube. The objective is thus to understand the influence of area reduction induced by the diaphragms, presence of two diaphragms, friction, shape of the diaphragms on shock attenuation. The commercial software Ansys Fluent had been employed to solve the two-dimensional and three-dimensional Navier-Stokes multispecies equations to obtain numerical solutions. The simulations were conducted with increasing complexity, thus from an inviscid ideal shock tube the most advanced simulation also included viscous effects, diaphragm shape and gradual diaphragm opening.
Experimental data comprise of pressure data and derived averaged shock speed data. Through the pressure measurements it was possible to measure the second diaphragm opening time to be approximately one millisecond. Results show that a decrease in diaphragm opening area results in a reduction of shock and contact discontinuity speed; A smaller opening results in a more gradual pressure rise thus a weaker shock. A larger opening time also promoted shock attenuation.

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