The effect of ambient pressure on ejecta sheets from free-surface ablation

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• 作者：J. O. Marston ; M. M. Mansoor ; S. T. Thoroddsen ; T. T. Truscott
• 刊名：Experiments in Fluids
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：57
• 期：5
• 全文大小：2,773 KB
• 刊物类别：Engineering
• 刊物主题：Engineering Fluid Dynamics
  Fluids
  Industrial Chemistry and Chemical Engineering
  Measurement Science and Instrumentation
  Thermodynamics
  Theoretical and Applied Mechanics
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1114
• 卷排序：57

文摘

We present observations from an experimental study of the ablation of a free liquid surface promoted by a focused laser pulse, causing a rapid discharge of liquid in the form of a very thin conical-shaped sheet. In order to capture the dynamics, we employ a state-of-the-art ultra-high-speed video camera capable of capturing events at \(5 \times 10^{6}\) fps with shutter speeds down to 20 ns, whereby we were able to capture not only the ejecta sheet, but also the shock wave, emerging at speeds of up to 1.75 km/s, which is thus found to be hypersonic (Mach 5). Experiments were performed at a range of ambient pressures in order to study the effect of air drag on the evolution of the sheet, which was always observed to dome over, even at pressures as low as 3.8 kPa. At reduced pressures, the extended sheet evolution led to the formation of interference fringe patterns from which, by comparison with the opening speed of rupture, we were able to determine the ejecta thickness.Electronic supplementary materialThe online version of this article (doi:10.1007/s00348-016-2141-9) contains supplementary material, which is available to authorized users.