scholarly journals The Kelvin impulse: application to cavitation bubble dynamics

1988 ◽  
Vol 30 (2) ◽  
pp. 127-146 ◽  
Author(s):  
J. R. Blake
Keyword(s):  
Fluid Mechanics ◽  
Cavitation Bubble ◽  
Bubble Dynamics ◽  
Velocity Potential ◽  
Pressure Field ◽  
Ring Vortex ◽  
Fluid Density ◽  
Cavitation Damage ◽  
Unsteady Fluid ◽  
Image Position

AbstractThe Kelvin impulse is a particularly valuable dynamical concept in unsteady fluid mechanics, with Benjamin and Ellis [2] appearing to be the first to have realised its value in cavitation bubble dynamics. The Kelvin impulse corresponds to the apparent inertia of the cavitation bubble and, like the linear momentum of a projectile, may be used to determine aspect It is defined aswhere ρ is the fluid density, ø is the velocity potential, S is the surface of the cavitation bubble and n is the outward normal to the fluid. Contributions to the Kelvin impulse may come from the presence of nearby boundaries and the ambient velocity and pressure field. With this number of mechanisms contributing to its development, the Kelvin impulse may change sign during the lifetime of the bubble. After collapse of the bubble, it needs to be conserved, usually in the form of a ring vortex. The Kelvin impulse is likely to provide valuable indicators as to the physical properties required of boundaries in order to reduce or eliminate cavitation damage. Comparisons are made against available experimental evidence.

The Pressure Field Radiated by Cavitation Bubble in the Grinding Area of Power Ultrasonic Honing

2014 ◽  
Vol 1027 ◽  
pp. 44-47 ◽  
Author(s):  
Xi Jing Zhu ◽  
Ce Guo ◽  
Jian Qing Wang
Keyword(s):  
Radiation Pressure ◽  
Cavitation Bubble ◽  
Bubble Dynamics ◽  
Pressure Field ◽  
Bubble Radius ◽  
Ultrasonic Frequency ◽  
Power Ultrasonic ◽  
Cutting Chatter ◽  
Grinding Mechanism ◽  
Order Of Magnitude

The pressure field induced by cavitaion bubble is responsible for the grinding mechanism and the cutting chatter of power ultrasonic honing. Based on the cavitation bubble dynamics model in the grinding area of power ultrasonic honing, the radiation pressure field of cavitation bubble was established. Experimental results show that the bubble is distributed in the grinding area like honeycomb and the size is about 10μm. Numerical simulation of dynamics and pressure field of cavitation bubble was performed. Numerical results show the dynamic behavior of cavitation bubble presents grow, expend and collapse under an acoustic cycle. However the expansion amplitude of bubble can be decreased and the collapse time can be extended and even collapse after several acoustic cycles with increasing ambient bubble radius. The bubble radiation pressure during collapsing bubble increases with increasing ultrasonic amplitude and ultrasonic frequency. And the pressure value of collapsing bubble is about 10Mpa which is more an order of magnitude than atmospheric pressure.

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.

Bubble dynamics and pressure field characteristics of underwater detonation gas jet generated by a detonation tube

2021 ◽  
Vol 33 (2) ◽  
pp. 023302
Author(s):  
Wei Liu ◽  
Ning Li ◽  
Chun-sheng Weng ◽  
Xiao-long Huang ◽  
Yang Kang
Keyword(s):  
Bubble Dynamics ◽  
Pressure Field ◽  
Gas Jet ◽  
Detonation Tube

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

scholarly journals Fluid boundaries shaping using the method of kinetic balance

2006 ◽  
Vol 10 (4) ◽  
pp. 153-162
Author(s):  
Miroslav Benisek ◽  
Svetislav Cantrak ◽  
Milos Nedeljkovic ◽  
Djordje Cantrak ◽  
Dejan Ilic ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Mechanics ◽  
Cross Sections ◽  
Hydraulic Engineering ◽  
Optimum Shape ◽  
Curved Channels ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid ◽  
Flow Boundaries ◽  
Dead Water

Fluid flow in curved channels with various cross-sections, as a common problem in theoretical and applied fluid mechanics, is a very complex and quite undiscovered phenomenon. Defining the optimum shape of the fluid flow boundaries, which would ensure minimum undesirable phenomena, like "dead water" zones, unsteady fluid flow, etc., is one of the crucial hydraulic engineering?s task. Method of kinetic balance is described and used for this purpose, what is illustrated with few examples. .

scholarly journals Intraocular Pressure Study in Ex Vivo Pig Eyes by the Laser-Induced Cavitation Technique: Toward a Non-Contact Intraocular Pressure Sensor

2020 ◽  
Vol 10 (7) ◽  
pp. 2281
Author(s):  
Santiago Camacho-Lopez ◽  
Carlos Andrés Zuñiga-Romero ◽  
Luis Felipe Devia-Cruz ◽  
Carolina Alvarez-Delgado ◽  
Marcos Antonio Plata-Sanchez ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Cavitation Bubble ◽  
Bubble Dynamics ◽  
Continuous Wave ◽  
Ex Vivo ◽  
Applanation Tonometry ◽  
Reliable Technique ◽  
Measurement Resolution ◽  
In Vivo Diagnosis

Traditional applanation tonometry techniques lack the necessary accuracy and reliability for measuring the intraocular pressure (IOP), and there is still a need for a reliable technique for in vivo diagnosis. A single laser-induced cavitation bubble event was optically monitored in order to precisely measure the first collapse time of the cavitation bubble, which presents a direct dependence on the liquid pressure. This can certainly be done within the IOP range. We now extend the partial transmittance modulation (STM) technique to determine its feasibility for directly measuring the IOP by studying the nanosecond (ns) pulsed laser-induced cavitation bubble dynamics for an externally pressurized fresh ex vivo porcine eye. The results demonstrate that it is possible to monitor the IOP by detecting the light of a continuous-wave (CW) laser beam which is intensity modulated by the bubble itself. This technique currently presents a measurement resolution of about 4 mmHg in the 5 to 50 mmHg pressure range, indicating the feasibility of this approach for measuring IOP. This technique provides a direct measurement within the anterior eye chamber, avoiding common pitfalls in IOP diagnosis, such as errors due to patient movement, varying physical properties of the eye globe, or central cornea thickness (CCT) effects.

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