Application of Multigrid Ghost Fluid Method to the Interaction of Shock Waves with Bubbles in Liquids

Kobayashi, Kazumichi; Jinbo, Yoshinori; Takahira, Hiroyuki

doi:10.1299/kikaib.77.20

Cited by 10 publications

(8 citation statements)

References 16 publications

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“…The initial velocities of both the gas and liquid phases were uniform, the initial pressures of both phases were 0.10 MPa, and the densities of the gas and liquid phases were 1.20 kg/m 3 and 1000 kg/m 3 , respectively. Adaptive zonal grids 26 were applied in the computation. The finest grid resolution and smallest time increment were 0.0025 mm and 5.0 × 10 −10 s, respectively.…”

Section: Experimental and Numerical Methodsmentioning

confidence: 99%

Observation of Water-Droplet Impacts with Velocities ofO(10 m/s) and Subsequent Flow Field

Tatekura

Fujikawa

Jinbo

et al. 2015

ECS J. Solid State Sci. Technol.

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A two-fluid spray cleaning technique has been gaining popularity as a cleaning process in the semiconductor industry. The most essential physical process in this technique is the impact of droplets with a velocity of O(10 m/s) on a solid surface. This study aims to experimentally and numerically investigate water-droplet impacts with velocities of up to 50 m/s and their subsequent flow fields, especially the gas flow field in the strictly limited area in the vicinity of the contact line. First, we experimentally evaluated the velocity of the splash and numerically calculated the gas velocities. Comparison of these velocities supported our assumption that the maximum gas velocity may be on approximately the same order as the velocity of the splash. Therefore, we concluded that the gas velocity field of the order of 500 m/s indeed develops at the impact of droplet with a velocity of the order of 50 m/s. Moreover, we determined that the gas pressure was of the order of 1.0 MPa by numerical analysis. Such a high pressure leads to shock wave propagation, which can contribute to the cleaning process in semiconductor production. To manufacture semiconductors, cleaning techniques that use physical action, such as megasonic agitation, are generally employed 1 together with those using chemical action to enhance the cleaning efficiency. A deionized water/gas-mixture jet spray cleaning technique, in other words, a two-fluid spray cleaning technique, is also gaining popularity.1-4 The advantage of this technique over megasonic agitation is the magnitude of the physical action generated by a highspeed droplet impacting a solid surface. However, most cleaning techniques that use physical action tend to cause structural damage and pattern collapse; therefore, the particle removal force should be quantitatively understood and measured. 5,6 The development of advanced spray technology offers the possibility of preventing this damage by controlling both the sizes and velocities of the droplets with extremely high accuracy. 7,8 It should be emphasized here that the most essential physical process in this two-fluid spray cleaning technique is the droplet impact upon the solid surface with a velocity of several tens of meters per second. Until recently, the velocities of liquid droplets in most experimental studies on liquid-droplet impacts were restricted to the range of several meters per second, 9-11 mainly due to the difficulties associated with high-speed observation. On the other hand, Mehdizadeh et al., 12 Pan et al., 13 and Visser et al. 14 reported on experimental studies that utilized droplet impacts at velocities of the order of 10 m/s. Mehdizadeh et al.12 observed the impacts of water droplets with radii of about 1 mm on stainless steel surface mounted on the end of a rotating arm whose linear velocities of up to 50 m/s. They measured the number of fingers and maximum diameter of the droplet after spreading. Pan et al. 13 observed the collision between a solid plate and a droplet with a radius of about 0.5 mm and a speed...

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Section: Experimental and Numerical Methodsmentioning

confidence: 99%

Observation of Water-Droplet Impacts with Velocities ofO(10 m/s) and Subsequent Flow Field

Tatekura

Fujikawa

Jinbo

et al. 2015

ECS J. Solid State Sci. Technol.

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“…Both interfaces are discriminated by the level set function, 𝜑, which is a signed distance function from the interface (Sussman et al, 1994). To distinguish between the three phases, two level set functions are defined as 𝜑 and 𝜑 (Kobayashi et al, 2011b). The gas-water interface and water-tissue interface are defined by the sets of 𝜑 = 0 and the sets of 𝜑 = 0, respectively.…”

Section: Interface Capturingmentioning

confidence: 99%

“…In the present calculations, 32 marker particles were distributed in each cell. Kobayashi et al (2011b) showed that it worked well in conserving the mass of the bubbles for the shock-bubble interactions. The third-order TVD-Runge Kutta scheme was used for time marching and the 5th order WENO scheme (Jiang and Peng, 2000) was used for convection terms.…”

Section: Interface Capturingmentioning

confidence: 99%

Numerical simulations for matter transport by the interaction between bubbles and pressure waves near tissue boundaries

MURASAWA,

KAMEDA,

TAKAHIRA

2024

JFST

Self Cite

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The interaction between bubbles and tissues (bone and fat) in ultrasound and the mechanism of drug transport accompanied by bubble collapse were investigated numerically by using the ghost fluid methods with zonal grids. A parameter defined by the ratio of 𝑡 to 𝑡 which is proportional to the ratio of bubble radius to wavelength, where 𝑡 is the bubble collapse time and 𝑡 is the period of an incident pressure wave, was used to characterize the relationship between the incident pressure waveform and the bubble collapse. It was found that the bubble collapse near a tissue surface was classified into three types by considering the penetration of liquid jet and bubble blobs into the tissues. The transport process of matter (imaginary drug) distributed around the bubble surface was calculated with the bubble collapse. The results showed that the mechanism of matter transport due to bubble collapse was summarized as follows. First, both the shock wave by the liquid jet impact on the bubble surface and the rebound shock wave lead to the depression of the tissue wall, and the matter is transported with the vortex flow due to liquid jet formation. Then, the bubble penetrates into the depression, increasing the amount of matter transported into the tissue. The bubble collapse and the matter transport in the bone wall case were compared with those in the fat wall case. Although the maximum wall pressure was higher in the bone case, the amount of matter transported inside the tissue was higher in the fat case. This was caused by the difference in the acoustic impedance between both tissues: the large acoustic impedance of bone induced the reflection of the incident wave, leading to the superposition of the incident wave and the reflection wave that contributed to the acceleration of bubble collapse. Since the stiffer property of bone suppressed the development of the vortex flow and the bubble growth inside the tissue, a larger circulation existed inside the fat, which contributed to the advection of the matter, resulting in a higher concentration of matter inside the fat than inside the bone.

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“…Since the liquid is assumed to be incompressible in the boundary element analysis, the physics of the shockwave cannot be treated. Therefore, we simulated the bubble collapse by solving Euler equations and a stiffened-gas equation of state [14] using the ghost fluid method [10][11][12] (GFM) with the level-set method [15,16]. Initial conditions are given at the maximum expansion of a bubble: the initial shapes of the bubble and free surfaces are given from the corresponding numerical results of the boundary element analysis.…”

Section: Numerical Studiesmentioning

confidence: 99%

“…In the experiment, a laser-induced bubble generated inside of a plain jet is observed using a high-speed video camera. The growth and collapse phases are simulated by the boundary element method (BEM) [8,9] and the collapse phase is also simulated by the ghost fluid method [10][11][12]. Figure 1 shows schematic diagrams of an experimental setup and a nozzle geometry to form a plane jet, respectively.…”

Section: Introductionmentioning

confidence: 99%

The Growth and Collapse of a Bubble between Parallel Flat Free Surfaces

Ogasawara¹,

S²,

Takahira³

2018

Proceedings of the 10th International Symposium on Cavitation (CAV2018)

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The growth and collapse of a bubble between two parallel flat free surfaces and the corresponding water column formation on the free surfaces have been investigated experimentally and numerically. In the experiment, a laser-induced bubble generated inside a plane water jet and the dynamical motion of free surfaces were observed with a high-speed video camera. The results are characterized by two dimensionless parameters: the ratio of the maximum bubble radius to the water jet width, Rmax * , and the ratio of the initial bubble offset from the center line of the jet to the water jet width, ε * .When a bubble is generated at the center (ε * = 0), water columns are formed on both free surfaces during the growth phase of a bubble, following the formation of crown-like shaped water columns during the second growth and collapse of a bubble. Since the bubble does not translates, it grows and collapses at the center of the jet. However, a water column due to the bubble growth when ε * ≠ 0 tends to be formed only on the nearer free surface to the bubble during its growth phase. Then in the collapse phase the bubble translates toward the other free surface far from the bubble accompanying with a liquid-jet formation toward it. The liquid-jet and the rebound shockwave from the bubble cause the water column formation on both sides of free surfaces. Numerical simulations are conducted for the growth and collapse phases using the boundary element method (BEM) and for the collapse phase using the ghost fluid method (GFM). The water column formation during the growth phase, a toroidal bubble deformation during the collapse phase, and the translation of the collapsing bubble are well simulated by BEM. The result of GFM shows shockwave emission from the rebounding motion of the bubble which causes the water column formation when the shockwave impacts on the free surface with large curvature.

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Application of Multigrid Ghost Fluid Method to the Interaction of Shock Waves with Bubbles in Liquids

Cited by 10 publications

References 16 publications

Observation of Water-Droplet Impacts with Velocities ofO(10 m/s) and Subsequent Flow Field

Observation of Water-Droplet Impacts with Velocities ofO(10 m/s) and Subsequent Flow Field

Numerical simulations for matter transport by the interaction between bubbles and pressure waves near tissue boundaries

The Growth and Collapse of a Bubble between Parallel Flat Free Surfaces

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