Shock wave and cavitation bubble dynamics during photodisruption in ocular media and their dependence on the pulse duration

1996 ◽  
Author(s):  
Tibor Juhasz ◽  
George Kastis ◽  
Carlos G. Suarez ◽  
Laszlo Turi ◽  
Zsolt Bor ◽  
...  
Keyword(s):  
Shock Wave ◽  
Pulse Duration ◽  
Cavitation Bubble ◽  
Bubble Dynamics ◽  
Ocular Media

Laser-induced cavitation phenomenon studied using three different optically-based approaches – An initial overview of results

2012 ◽  
Vol 1 (3) ◽  
Author(s):  
Luis F. Devia-Cruz ◽  
Santiago Camacho-López ◽  
Rodger Evans ◽  
Daniel García-Casillas ◽  
Sergei Stepanov
Keyword(s):  
Shock Wave ◽  
Cavitation Bubble ◽  
Bubble Dynamics ◽  
Laser Pulses ◽  
Laser Flash ◽  
External Pressure ◽  
Maximum Diameter ◽  
Probe Laser ◽  
Nanosecond Laser ◽  
Pressurized Water

AbstractThis report presents a study of shock wave and cavitation bubble dynamics induced by nanosecond laser pulses in pressurized water. Three methods were used to obtain data from the irradiated sample: (1) pump-probe laser flash shadowgraphy, (2) pressure wave sensing by means of a fiber optic interferometer hydrophone, and (3) a novel technique based on the modulation of spatial transmittance by the cavitation bubble. The medium used in these experiments was distilled water in a chamber under different pressure conditions which included values found in human intraocular liquid. It could be shown that while external pressure does not affect either the shock wave propagation or the initial bubble growth rate, it does affect the first collapse time of the bubble and its maximum diameter.

scholarly journals Numerical Study on the Potential of Cavitation Damage in a Lead–Bismuth Eutectic Spallation Target

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 681
Author(s):  
Tao Wan ◽  
Takashi Naoe ◽  
Hiroyuki Kogawa ◽  
Masatoshi Futakawa ◽  
Hironari Obayashi ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Proton Beam ◽  
Pulse Duration ◽  
Cavitation Bubble ◽  
Bubble Dynamics ◽  
Metal Flow ◽  
Test Facility ◽  
Cavitation Damage ◽  
Spallation Target ◽  
Liquid Metal Flow

To perform basic Research and Development for future Accelerator-driven Systems (ADSs), Japan Proton Accelerator Research Complex (J-PARC) will construct an ADS target test facility. A Lead–Bismuth Eutectic (LBE) spallation target will be installed in the target test facility and bombarded by pulsed proton beams (250 kW, 400 MeV, 25 Hz, and 0.5 ms pulse duration). To realize the LBE spallation target, cavitation damage due to pressure changes in the liquid metal should be determined, preliminarily, because such damage is considered to be very critical, from the viewpoint of target safety and lifetime. In this study, cavitation damage due to pressure waves caused by pulsed proton beam injection and turbulent liquid metal flow, were studied, numerically, from the viewpoint of single cavitation bubble dynamics. Specifically, the threshold of cavitation and effects of flow speed fluctuation on cavitation bubble dynamics, in an orifice structure, were investigated in the present work. The results showed that the LBE spallation target did not undergo cavitation damage, under normal nominal operation conditions, mainly because of the long pulse duration of the pulsed proton beam and the low liquid metal flow velocity. Nevertheless, the possibility of cavitation damage in the orifice structure, under certain extreme transient LBE flow conditions, cannot be neglected.

Data assimilation for modeling cavitation bubble dynamics

2021 ◽  
Vol 62 (5) ◽  
Author(s):  
Javad Eshraghi ◽  
Arezoo M. Ardekani ◽  
Pavlos P. Vlachos
Keyword(s):  
Data Assimilation ◽  
Cavitation Bubble ◽  
Bubble Dynamics

Early Dynamics of a Laser-induced Underwater Shock Wave

2021 ◽  
Author(s):  
Guihua Lai ◽  
Siyuan Geng ◽  
Hanwen Zheng ◽  
Zhifeng Yao ◽  
Qiang Zhong ◽  
...  
Keyword(s):  
Shock Wave ◽  
Numerical Method ◽  
Cavitation Bubble ◽  
Laser Energy ◽  
Optical Breakdown ◽  
Pulsed Laser ◽  
Underwater Shock Wave ◽  
Time Resolved ◽  
High Attenuation ◽  
Nanosecond Pulsed Laser

Abstract The objective of this paper is to observe and investigate the early evolution of the shock wave, induced by a nanosecond pulsed laser in still water. A numerical method is performed to calculate the propagation of the shock wave within 1µs, after optical breakdown, based on the Gilmore model and the Kirkwood-Bethe hypothesis. The input parameters of the numerical method include the laser pulse duration, the size of the plasma and the maximally extended cavitation bubble, which are measured utilizing a high time-resolved shadowgraph system. The calculation results are verified by shock wave observation experiments at the cavitation bubble expansion stage. The relative errors of the radiuses and the velocity of the shock wave front, reach the maximum value of 45% at 5 ns after breakdown and decrease to less than 20% within 20 ns. The high attenuation characteristics of the shock wave after the optical breakdown, are predicted by the numerical method. The quick time and space evolution of the shock wave are carefully analyzed. The normalized shock wave width is found to be independent of the laser energy and duration, and the energy partitions ratio is around 2.0 using the nanosecond pulsed laser.

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