《09 The counter jet formation in an air bubble induced by the impact of shock waves》.pdf

562 2011,23(5):562-569 DOI: 10.1016/S1001-6058(10)60150-3 THE COUNTER-JET FORMATION IN AN AIR BUBBLE INDUCED BY * THE IMPACT OF SHOCK WAVES BAI Li-xin Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China, E-mail: lixin.bai@ XU Wei-lin State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China LI Chao Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China GAO Yan-dong School of Electronic and Information Engineering, Liaoning Technical University, Huludao 125105, China (Received January 6, 2011, Revised March 29, 2011) Abstract: The interaction of an air bubble (isolated in water or attached to a boundary) with shock waves induced by electric sparks is investigated by high-speed photography. The interaction is closely related to the counter-jet induced by the impact of shock waves. The formation of a counter-jet in an air bubble is related to the liquid jet formed in the same air bubble, but the mechanism is different with that of the counter-jet formation in a collapsing cavitation bubble. The formation of a counter-jet in an air bubble is related to discharge energy, air bubble size and radius of shock wave. With a given energy of the spark discharge, the formation of a counter-jet in an air bubble is related to δ / ε (the ratio of the dimensionless bubble-bubble distance to the dimensionless air bubble radius). The counter-jet will only be produced when δ / ε is in the range of 1.2-2.2. The counter-jet in an air bubble is of an important nuclei-generating mechanism. Key words