業績情報

• Revealing the sound, flow excitation, and collision dynamics of human handclaps　　　　　　　　　　　　　　　
  Yicong Fu; Akihito Kiyama; Guoqin Liu; Likun Zhang; Sunghwan Jung
  Physical Review Research, 2025年03月, ［査読有り］, ［国際共著］, ［国際誌］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1103/PhysRevResearch.7.013259
  DOI ID：10.1103/PhysRevResearch.7.013259, ORCID：179813589
• Pressure fluctuations of liquids under short-time acceleration　　　　　　　　　　　　　　　
  Chihiro Kurihara; Akihito Kiyama; Yoshiyuki Tagawa
  Journal of Fluid Mechanics, 2025年01月, ［査読有り］, ［国際誌］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1017/jfm.2024.1190
  DOI ID：10.1017/jfm.2024.1190, ORCID：175871127
• Altered deep-seal water entry behavior of a sphere by a neighboring sphere and/or solid boundary　　　　　　　　　　　　　　　
  Rafsan Rabbi; Chase Mortensen; Akihito Kiyama; Tadd Truscott
  Ocean Engineering, 2024年12月, ［査読有り］, ［国際共著］, ［国際誌］
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.oceaneng.2024.119377
  DOI ID：10.1016/j.oceaneng.2024.119377, ORCID：169717268, 共同研究・競争的資金等ID：46268606
• Toroidal cavitation by a snapping popper　　　　　　　　　　　　　　　
  Akihito Kiyama; Sharon Wang; Jisoo Yuk; Sunghwan Jung
  Physical Review Fluids, 2024年03月, ［査読有り］, ［招待有り］, ［筆頭著者］, ［国際共著］, ［国際誌］
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1103/PhysRevFluids.9.030501
  DOI ID：10.1103/PhysRevFluids.9.030501, ORCID：155802203, 共同研究・競争的資金等ID：43444307
• On the interaction of two cavitation bubbles produced at different times: A jet from the primary bubble　　　　　　　　　　　　　　　
  Shingo Terasaki; Akihito Kiyama; Donghyuk Kang; Yukio Tomita; Kotaro Sato
  Physics of Fluids, 巻：36, 号：1, 2024年01月, ［査読有り］, ［国際誌］
  The liquid jet formation upon the collapse of two interacting cavitation bubbles is a physics-rich complex problem, which has possible implications such as the membrane sonoporation. In this paper, we employed both experiment and numerical simulations to study the jet behavior in a bubble, which is affected by another one introduced at various time delays. We provided the regime diagram, which shows the transition of the jet direction as a function of time delay and distance between bubbles. The maximum velocity of the jet in the primary bubble was investigated. The highest velocity was achieved when the primary bubble split into two parts upon collapse. It was found that a high curvature on the rim of the collapsing primary bubble causes the lateral pinch-off, leading to the formation of a fast and thin vertical jet approaching the secondary bubble. The results would help design an effective sonoporation system. The physics depicted in this manuscript might also contribute to the deeper understanding of the jet in a bubble interacting with not only another bubble but also other boundaries.
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1063/5.0180920
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85182279485&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85182279485&origin=inward
  DOI ID：10.1063/5.0180920, ISSN：1070-6631, eISSN：1089-7666, SCOPUS ID：85182279485, 共同研究・競争的資金等ID：43444307
• Droplet lift-off from hydrophobic surfaces from impact with soft-hydrogel spheres
  Rafsan Rabbi; Akihito Kiyama; John S. Allen; Tadd Truscott
  Communications Physics, 巻：5, 号：1, 2022年12月, ［査読有り］, ［国際共著］, ［国際誌］
  Abstract
  
  Droplet impacts on superhydrophobic surfaces may result in complete bouncing, with the absence of contact hysteresis and viscous dissipation leading the droplet to fully rebound off the surface. This rebound usually happens in the retraction phase, when the droplet retracts back after reaching a maximum spread diameter. Here, we present experimental evidence of a bouncing phenomenon where a sessile droplet on a hydrophobic surface bounces off the surface in its spreading phase when a soft deformable hydrogel sphere axisymmetrically impacts the droplet. We term this as ‘Lift-Off’ and propose a simple force balance based on the deformation characteristics of the hydrogel sphere to explain the out-of-plane jump of the droplet during spreading. We observe three different impact regimes, and propose their dependency on a modified elastic ‘Mach’ number (Ma^*) with Ma^* ≈ 0.1 corresponding to the onset of lift-off. We also report on the unique acoustic signatures of lift-off cases, associated with the capture of air-bubbles through the air-borne retracting droplet rim. These results may have potential applications for drainage and surface cleaning, non-stick surface coating, industrial mixing and plant disease spreading.
  Springer Science and Business Media LLC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1038/s42005-022-01114-8
  DOI ID：10.1038/s42005-022-01114-8, eISSN：2399-3650, ORCID：125173785
• Morphology of bubble dynamics and sound in heated oil
  Akihito Kiyama; Rafsan Rabbi; Zhao Pan; Som Dutta; John S Allen; Tadd T Truscott
  Physics of Fluids, 巻：34, 号：6, 開始ページ：062107, 終了ページ：062107, 2022年06月, ［査読有り］, ［筆頭著者］, ［国際共著］, ［国際誌］
  The interaction between a heated oil bath and water droplets commonly occurs in the kitchen and has important implications for cooking, fire safety, and indoor air pollution. The interplay between the bubble dynamics in a heated oil bath, the generated sound, and the ligament-like expulsion to the surrounding air is examined. We focus on an explosion of a millimeter-sized water droplet in heated oil as a simplified case. We discuss three typical bubble types that can be classified as a function of the stand-off parameter h/ R, where h is the distance between the oil surface and bubble and R is the maximum bubble radius. Our data describe the morphology of bubble dynamics inside a heated oil bath and represent those found in the cooking pan. This paper also highlights potential applications of our findings.
  AIP Publishing, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1063/5.0088065
  DOI ID：10.1063/5.0088065, ISSN：1070-6631, eISSN：1089-7666, ORCID：114117710
• Direction of the microjet produced by the collapse of a cavitation bubble located in a corner of a wall and a free surface　　　　　　　　　　　　　　　
  Akihito Kiyama; Takaaki Shimazaki; José Manuel Gordillo; Yoshiyuki Tagawa
  Physical Review Fluids, 2021年08月, ［査読有り］, ［筆頭著者］, ［国際共著］, ［国際誌］
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1103/PhysRevFluids.6.083601
  DOI ID：10.1103/PhysRevFluids.6.083601, ORCID：98105114
• Ouzo Column under Impact: Formation of Emulsion Jet and Oil-Lubricated Droplet　　　　　　　　　　　　　　　
  Kyota Kamamoto; Akihito Kiyama; Yoshiyuki Tagawa; Xuehua Zhang
  Langmuir, 巻：37, 号：6, 開始ページ：2056, 終了ページ：2064, 2021年02月, ［査読有り］, ［国際共著］, ［国際誌］
  We investigated the dynamics of a liquid column consisting of ouzo emulsion under the impact generated when the liquid container lands on a hard ground. At a cavitation number of 0.36, where cavitation is expected to occur, our high-speed videography captured the traveling jet and cavitation bubbles while the oil microdroplets in ouzo after different runs of impact were visualized by an optical microscope. Importantly, the impact on an ouzo column can eject a focused jet of the emulsion and deposit a small volume of emulsion on a solid substrate. As revealed by our still photography, the deposited emulsion formed an oil-lubricated drop immediately. Our findings have implications for jetting applications such as inkjet printing of emulsions or fast deposition of self-lubricating drops for assembling supraparticles. We also discuss the jet formation mechanism in terms of the existence of oil microdroplets.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acs.langmuir.0c01692
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100749903&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85100749903&origin=inward
  DOI ID：10.1021/acs.langmuir.0c01692, ISSN：0743-7463, eISSN：1520-5827, PubMed ID：33527827, SCOPUS ID：85100749903
• Size Effect on the Reaction Rate of Surface Nanodroplets　　　　　　　　　　　　　　　
  Zhengxin Li; Akihito Kiyama; Hongbo Zeng; Xuehua Zhang
  Journal of Physical Chemistry C, 2021年, ［査読有り］, ［国際共著］
  Compartmentalizing reagents within small droplets is promising for highly efficient conversion and simplified procedures in many biphasic chemical reactions. In this work, surface nanodroplets (i.e., less than 100 nm in their maximal height) were employed to quantitatively understand the size effect on the chemical reaction rate of droplets. In our systems, a surface-active reactant in pure or binary nanodroplets reacted with the reactant in the bulk flow. Meanwhile, the product was removed from the droplet surface. The shrinkage rate of the nanodroplets was characterized by analyzing the lateral size as a function of time, where the droplet size was solely determined by the chemical reaction rate under a given flow condition for the transport of the reactant and the product. We found that the overall kinetics increases rapidly with the decrease in droplet's lateral radius R, as dR/dt ∼R-2. The faster increase in the concentration of the product in smaller droplets contributes to accelerating reaction kinetics. The enhancement of reaction rates from small droplet sizes was further confirmed when a nonreactive compound was present inside the droplets without reducing the concentrations of the reactant and the product on the droplet surface. The results of our study improve the understanding of chemical kinetics with droplets. Our findings highlight the effectiveness of small droplets for the design and control of enhanced chemical reactions in a broad range of applications.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acs.jpcc.1c04092
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85111199084&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85111199084&origin=inward
  DOI ID：10.1021/acs.jpcc.1c04092, ISSN：1932-7447, eISSN：1932-7455, SCOPUS ID：85111199084
• Impact force reduction by consecutive water entry of spheres　　　　　　　　　　　　　　　
  Rafsan Rabbi; Nathan B. Speirs; Akihito Kiyama; Jesse Belden; Tadd T. Truscott
  Journal of Fluid Mechanics, 巻：915, 2021年, ［査読有り］, ［国際共著］, ［国際誌］
  Free-falling objects impacting onto water pools experience a very high initial impact force, greatest at the moment when breaking through the free surface. Many have intuitively wondered whether throwing another object in front of an important object (like oneself) before impacting the water surface may reduce this high impact force. Here, we test this idea experimentally by allowing two spheres to consecutively enter the water and measuring the forces on the trailing sphere. We find that the impact acceleration reduction on the trailing sphere depends on the dynamics of the cavity created by the first sphere and the relative timing of the second sphere impact. These combined effects are captured by the non-dimensional 'Matryoshka' number, which classifies the observed phenomena into four major regimes. In three of these regimes, we find that the impact acceleration on the second sphere is reduced by up to 78 % relative to impact on a quiescent water surface. Surprisingly, in one of the regimes the force on the trailing sphere is dramatically increased by more than 400 % in the worst case observed. We explain how the various stages of cavity evolution result in the observed alterations in impact force in this multi-body water entry problem.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1017/jfm.2020.1165
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85102783839&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85102783839&origin=inward
  DOI ID：10.1017/jfm.2020.1165, ISSN：0022-1120, eISSN：1469-7645, SCOPUS ID：85102783839
• Speeding up biphasic reactions with surface nanodroplets　　　　　　　　　　　　　　　
  Zhengxin Li; Akihito Kiyama; Hongbo Zeng; Detlef Lohse; Xuehua Zhang
  Lab on a Chip, 巻：20, 号：16, 開始ページ：2965, 終了ページ：2974, 2020年08月, ［査読有り］, ［国際共著］, ［国際誌］
  Biphasic chemical reactions compartmentalized in small droplets offer advantages, such as streamlined procedures for chemical analysis, enhanced chemical reaction efficiency and high specificity of conversion. In this work, we experimentally and theoretically investigate the rate for biphasic chemical reactions between acidic nanodroplets on a substrate surface and basic reactants in a surrounding bulk flow. The reaction rate is measured by droplet shrinkage as the product is removed from the droplets by the flow. In our experiments, we determine the dependence of the reaction rate on the flow rate and the solution concentration. The theoretical analysis predicts that the life time τ of the droplets scales with Peclet number Pe and the reactant concentration in the bulk flow cre,bulk as τ ∝ Pe-3/2cre,bulk-1, in good agreement with our experimental results. Furthermore, we found that the product from the reaction on an upstream surface can postpone the droplet reaction on a downstream surface, possibly due to the adsorption of interface-active products on the droplets in the downstream. The time of the delay decreases with increasing Pe of the flow and also with increasing reactant concentration in the flow, following the scaling same as that of the reaction rate with these two parameters. Our findings provide insight for the ultimate aim to enhance droplet reactions under flow conditions. This journal is
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/d0lc00571a
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85089407241&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85089407241&origin=inward
  DOI ID：10.1039/d0lc00571a, ISSN：1473-0197, eISSN：1473-0189, PubMed ID：32780079, SCOPUS ID：85089407241
• Visualization of penetration of a high-speed focused microjet into gel and animal skin　　　　　　　　　　　　　　　
  Akihito Kiyama; Nanami Endo; Sennosuke Kawamoto; Chihiro Katsuta; Kumiko Oida; Akane Tanaka; Yoshiyuki Tagawa
  Journal of Visualization, 巻：22, 号：3, 開始ページ：449, 終了ページ：457, 2019年06月, ［査読有り］, ［筆頭著者］, ［国際誌］
  Abstract: Realization of a needle-free drug delivery device can solve needle-caused problems. Recently, attention has been given to the use of a focused liquid jet instead of the use of the existing needle-free device that generates a turbulent liquid jet. This study experimentally visualized the penetration into a gel and animal skin of a focused liquid jet with a very high speed around 200 m/s. We first examined high-speed images to evaluate the dynamics of the jet penetration into a gel. We found that the penetration depth is determined within a short time t p (on the order of 0.01 ms). t p is similar to L/ V j , where L and V j are, respectively, the penetration depth and the impact speed of the jet tip. We then investigated the overall shape of the penetration site represented by the length ratio α= L/ W, where W is the width of the penetration site. Remarkably, the ratio α is greater than unity for a gel, as well as for the animal skin. This suggests that the focused liquid jet can create a narrow penetration site into the target. Graphical abstract: [Figure not available: see fulltext.]
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s12650-019-00547-8
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85065889236&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85065889236&origin=inward
  DOI ID：10.1007/s12650-019-00547-8, ISSN：1343-8875, eISSN：1875-8975, SCOPUS ID：85065889236
• PVAゲルを用いた新規インクジェット射出速度の制御手法　　　　　　　　　　　　　　　
  前嶋麻緒; 工藤帆乃香; 大貫甫; 栗原千尋; 木山景仁; 田川義之
  日本画像学会誌, 巻：58, 号：1, 2019年, ［査読有り］, ［国内誌］
  日本語, 研究論文（学術雑誌）
  ISSN：1344-4425, J-Global ID：201902228906072872
• Gelatine cavity dynamics of high-speed sphere impact　　　　　　　　　　　　　　　
  Akihito Kiyama; Mohammad M. Mansoor; Nathan B. Speirs; Yoshiyuki Tagawa; Tadd T. Truscott
  Journal of Fluid Mechanics, 開始ページ：707, 終了ページ：722, 2019年, ［査読有り］, ［筆頭著者］, ［国際共著］, ［国際誌］
  We investigate the impact and penetration of a solid sphere passing through gelatine at various impact speeds up to. Tests were performed with several concentrations of gelatine. Impacts for low elastic Froude number, a ratio between inertia and gelatine elasticity, resulted in rebound. Higher values resulted in penetration, forming cavities with prominent surface textures. The overall shape of the cavities resembles those observed in water-entry experiments, yet they appear in a different order with respect to increasing inertia: rebound, quasi-seal, deep-seal, shallow-seal and surface-seal. Remarkably, similar to the - phase diagram in water-entry experiments, the elastic Froude number and elastic Grashof number (a ratio between gravity and gelatine elasticity) classify all five different phenomena into distinguishable regimes. We find that can be a good indicator to describe the cavity length, particularly in the shallow-seal regime. Finally, the evolution of cavity shape, pinch-off depth, and lower cavity radius are investigated for different values.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1017/jfm.2019.696
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85073550308&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85073550308&origin=inward
  DOI ID：10.1017/jfm.2019.696, ISSN：0022-1120, eISSN：1469-7645, SCOPUS ID：85073550308
• Enhancement of Focused Liquid Jets by Surface Bubbles　　　　　　　　　　　　　　　
  Ryosuke Yukisada; Akihito Kiyama; Xuehua Zhang; Yoshiyuki Tagawa
  Langmuir, 巻：34, 号：14, 開始ページ：4234, 終了ページ：4240, 2018年04月, ［査読有り］, ［国際共著］, ［国際誌］
  We investigate the enhancement of the velocity of focused liquid jets by surface bubbles preformed on the inner surface of the container. The focused jets are created from the impact on a liquid-filled cylindrical tube at cavitation numbers of 0.37 (strong impact where cavitation is likely to occur on unprocessed surfaces) and 2.1 (weak impact where cavitation does not occur from the impact). The bubbles with a base diameter up to hundreds of micrometers were formed via the process of solvent exchange using air-equilibrated ethanol and water. Our measurements by high-speed imaging show that at both cavitation numbers, the jet velocities with preformed bubbles are significantly higher than those without preformed bubbles. Furthermore, our results show that after the process of solvent exchange, a large number of expanding bubbles are observed at cavitation number of 0.37, indicating that possibly both sub-millimeter and sub-micrometer bubbles on the surface contribute to the jet velocity enhancement. At the cavitation number of 2.1, the surface bubbles are observed to oscillate immediately after the impact. The measurements of the liquid pressure after the impact reveal that at both cavitation numbers, the negative pressure is damped by the preformed surface bubbles, contributing to the increase of the jet velocity. This work sheds light on the crucial role of surface bubbles on the impulsive motion of liquids. Our findings have significant implications for the focusing jet technology, opening the opportunities for jetting fragile samples such as biological samples.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acs.langmuir.8b00246
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85045193489&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85045193489&origin=inward
  DOI ID：10.1021/acs.langmuir.8b00246, ISSN：0743-7463, eISSN：1520-5827, PubMed ID：29551073, SCOPUS ID：85045193489
• Growth dynamics of surface nanodroplets during solvent exchange at varying flow rates　　　　　　　　　　　　　　　
  Brendan Dyett; Akihito Kiyama; Maaike Rump; Yoshiyuki Tagawa; Detlef Lohse; Xuehua Zhang
  Soft Matter, 巻：14, 号：25, 開始ページ：5197, 終了ページ：5204, 2018年, ［査読有り］, ［国際共著］, ［国際誌］
  Solvent exchange is a simple solution-based process to produce surface nanodroplets over a large area. The final size of the droplets is determined by both the flow and solution conditions for a given substrate. In this work, we investigate the growth dynamics of surface nanodroplets during solvent exchange by using total internal reflection fluorescence microscopy (TIRF). The results show that during the solvent exchange, the formation of surface nanodroplets advanced on the surface in the direction of the flow. The time for the number density and surface coverage of the droplets to reach their respective plateau values is determined by the flow rate. From the observed evolution of the droplet volume and of the size of individual growing droplets, we are able to determine that the growth time of the droplets scales with the Peclet number Pe with a power law ∝Pe-1/2. This is consistent with Taylor-Aris dispersion, shedding light on the diffusive growth dynamics during the solvent exchange. Further, the spatial rearrangement of the droplets during coalescence demonstrates a preference in position shift based on size inequality, namely, the coalesced droplet resides closer to the larger of the two parent droplets. These findings provide a valuable insight toward controlling droplet size and spatial distribution.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c8sm00705e
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85049349564&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85049349564&origin=inward
  DOI ID：10.1039/c8sm00705e, ISSN：1744-683X, eISSN：1744-6848, PubMed ID：29780988, SCOPUS ID：85049349564
• Effects of pressure impulse and peak pressure of a shockwave on microjet velocity in a microchannel　　　　　　　　　　　　　　　
  Keisuke Hayasaka; Akihito Kiyama; Yoshiyuki Tagawa
  Microfluidics and Nanofluidics, 巻：21, 号：11, 2017年11月, ［査読有り］, ［国際誌］
  We experimentally investigate the effect of a shockwave on the velocity of a microjet and underwater cavitation onset in a microchannel, focusing on the pressure impulse and peak pressure of the shockwave. The pressure impulse and peak pressure of the shockwave are separately varied by using non-spherical laser-induced shockwaves (Tagawa et al. in J Fluid Mech 808:5–18, 2016). We conduct two kinds of experiments. In one experiment, we install a narrow tube and a hydrophone in different configurations in large water-filled tank. We measure the shockwave pressure and the jet velocity simultaneously in order to elucidate the effects of pressure profile of shockwaves on the jet velocity. In the other experiment, we record the jet formation and cavitation onset to investigate the effect of cavitation onset on the jet velocity in an L-shaped microchannel. The experimental results suggest that the jet velocity depends only on the pressure impulse of the shockwave, while the probability of cavitation onset depends only on the peak pressure of the shockwave. The above findings provide new insights for advancing a control method for high-speed microjets.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s10404-017-2004-6
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85032348903&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85032348903&origin=inward
  DOI ID：10.1007/s10404-017-2004-6, ISSN：1613-4982, eISSN：1613-4990, SCOPUS ID：85032348903
• Cavitation onset caused by acceleration　　　　　　　　　　　　　　　
  Zhao Pan; Akihito Kiyama; Yoshiyuki Tagawa; David J. Daily; Scott L. Thomson; Randy Hurd; Tadd T. Truscott
  Proceedings of the National Academy of Sciences of the United States of America, 巻：114, 号：32, 開始ページ：8470, 終了ページ：8474, 2017年08月, ［査読有り］, ［筆頭著者］, ［国際共著］, ［国際誌］
  Striking the top of a liquid-filled bottle can shatter the bottom. An intuitive interpretation of this event might label an impulsive force as the culprit in this fracturing phenomenon. However, high-speed photography reveals the formation and collapse of tiny bubbles near the bottom before fracture. This observation indicates that the damaging phenomenon of cavitation is at fault. Cavitation is well known for causing damage in various applications including pipes and ship propellers, making accurate prediction of cavitation onset vital in several industries. However, the conventional cavitation number as a function of velocity incorrectly predicts the cavitation onset caused by acceleration. This unexplained discrepancy leads to the derivation of an alternative dimensionless term from the equation of motion, predicting cavitation as a function of acceleration and fluid depth rather than velocity. Two independent research groups in different countries have tested this theory; separate series of experiments confirm that an alternative cavitation number, presented in this paper, defines the universal criteria for the onset of acceleration-induced cavitation.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1073/pnas.1702502114
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85026857242&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85026857242&origin=inward
  DOI ID：10.1073/pnas.1702502114, ISSN：0027-8424, eISSN：1091-6490, PubMed ID：28739956, SCOPUS ID：85026857242
• Effects of a water hammer and cavitation on jet formation in a test tube　　　　　　　　　　　　　　　
  Akihito Kiyama; Yoshiyuki Tagawa; Keita Ando; Masaharu Kameda
  Journal of Fluid Mechanics, 巻：787, 開始ページ：224, 終了ページ：236, 2015年12月, ［査読有り］, ［筆頭著者］, ［国際誌］
  We investigate the motion of a gas-liquid interface in a test tube induced by a large acceleration via impulsive force. We conduct simple experiments in which the tube partially filled with a liquid falls under gravity and hits a rigid floor. A curved gas-liquid interface inside the tube reverses and eventually forms a so-called focused jet. In our experiments, there arises either vibration of the interface or an increment in the velocity of the liquid jet, accompanied by the onset of cavitation in the liquid column. These phenomena cannot be explained by a considering pressure impulse in a classical potential flow analysis, which does not account for finite speeds of sound or phase changes. Here we model such water-hammer events as a result of the one-dimensional propagation of a pressure wave and its interaction with boundaries through acoustic impedance mismatching. The method of characteristics is applied to describe pressure-wave interactions and the subsequent cavitation. The model proposed is found to be able to capture the time-dependent characteristics of the liquid jet.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1017/jfm.2015.690
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84950156216&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84950156216&origin=inward
  DOI ID：10.1017/jfm.2015.690, ISSN：0022-1120, eISSN：1469-7645, SCOPUS ID：84950156216
• 撃力による液体ジェットの生成(ジェット速度に関する実験的研究)　　　　　　　　　　　　　　　
  木山景仁; 野口悠斗; 田川義之
  日本機械学会論文集(Web), 巻：80, 号：814, 2014年, ［査読有り］, ［筆頭著者］, ［国内誌］
  英語, 研究論文（学術雑誌）
  ISSN：2187-9761, J-Global ID：201402277841836492

• Two-Layer Liquid Sloshing Produced by Horizontal Excitation　　　　　　　　　　　　　　　
  Daiki Iwaya; Ryuichi Inoue; Akihito Kiyama; Donghyuk Kang; Kazuhiko Yokota; Kotaro Sato
  2024年
  Many studies on single-layer sloshing have been carried out due to accidents involving damage to floating roofs in oil tanks caused by long-period earthquakes and technical issues in the transport of liquids by ships [1]. Research on two-layer sloshing is currently needed to examine seismic resistance and to ensure safety in situations in which two-layer liquids are mixed, such as floating production systems that are used in offshore resource development as well as tuned liquid dampers that are used as vibration control systems for buildings [2]. To study two-layer sloshing, Veletsos and Shivakumar [3] derived a linear analytical solution and showed that the natural frequency depends on the tank width, depth of the two liquids, and density ratio. Lin et al. [4] experimentally investigated the resonant and non-resonant responses of a two-layer liquid in a tank under pitch excitation and found that when the excitation frequency is equal to the natural frequency of the free surface, resonance occurs at the free surface, whereas the wave height at the liquid-liquid interface is much smaller than that at the free surface. However, the wave height at the liquid-liquid interface may show in-phase motion that follows the motion of the free surface, although the wave height is considerably smaller than that of the free surface. There have been few existing studies on the sloshing of bilayer liquids, and only fragmentary findings have been obtained thus far. Therefore, this study focuses on the effect of the depth ratio of the two liquids on the vibration characteristics of two-layer liquid sloshing. Horizontal excitation experiments using a two-dimensional rectangular tank are conducted, and visual observations are made. The main results show that when the depth ratio of the two liquids (=height of the upper liquid / height of the lower liquid) is small, the motions of the free surface and the liquid-liquid interface are in phase during resonance, and the wave heights of the two liquids are close. When the depth ratio of the two liquids is unity, the resonant responses of the upper and lower liquids are confirmed to be in the lower-order mode, but the wave height of the lower liquid is lower than that observed with a smaller depth ratio.
  DOI：https://doi.org/10.11159/htff24.188
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85205103026&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85205103026&origin=inward
  DOI ID：10.11159/htff24.188, eISSN：2369-8136, SCOPUS ID：85205103026
• Observation of Two-Dimensional Bubble Motions near Various Boundaries　　　　　　　　　　　　　　　
  Ryuichi Inoue; Daiki Iwaya; Akihito Kiyama; Donghyuk Kang; Kotaro Sato
  2024年
  In recent years, the environment surrounding cavitation bubbles has significantly changed. Because cavitation causes material damage and abnormal vibrations in turbomachinery, they are regarded as challenging, and research has focused on suppressing them. However, research on flow generation that actively utilizes the kinetic characteristics of bubbles, such as sonoporation using jet formation in the microregion of cavitation bubbles [1] and the generation of synthetic jets by the nonlinear volume fluctuations of bubbles [2], has recently attracted attention. The motion of a cavitation bubble is generally expressed by the upwelling and suction (without momentum) of a potential flow; therefore, it is necessary to restrict the motion of the bubble to generate a directional flow with momentum using bubbles. Therefore, the behavior of bubbles under various boundary conditions in addition to rigid plates and free surfaces should be clarified. Tomita et al. conducted experimental and theoretical studies on curved rigid boundaries and elucidated the effect of rigid-body curvature on bubble motion [3]. Li et al. performed numerical simulations on the collapse behavior of a single bubble and two bubbles in an inclined V-shaped corner and established the relationship between the angle of the V-shaped corner, the distance between the corner and cavitation bubbles, and the distance between bubbles by obtaining the temperature, density, velocity, and pressure fields [4]. Yin et al. generated laser-induced single bubbles at the tip of a conical rigid body and determined the relative distance between the bubbles from the tip of the conical rigid body; they also investigated the effect of the cone angle on the pressure peak and other parameters through experimental and numerical studies [5]. However, these studies were conducted on three-dimensional (3D, axisymmetric) bubbles but are unsuitable for generating two-dimensional (2D) flows. In this study, a roughly 2D bubble was generated in a liquid between flat plates by electrical discharge, and its behavior was filmed at high speed. The motion of 2D bubbles under rigid wall conditions with various geometries was clarified, focusing mainly on the relationship between the wall geometry and time characteristics, and the difference between 2D and 3D bubbles was analyzed. The results show that the dimensionless collapse period θθ=90° increases as the dimensionless distance llww∗ (the ratio of the distance between the wall and the bubble to the maximum bubble equivalent radius) decreases. The value of the dimensionless collapse period ττ∗ for θθ=90° exceeds that of θθ=180° when the rigid body boundary angle θθ=180° (flat wall) and θθ=90° (L-shaped wall) are compared for the dimensionless distance llww∗. The value of the dimensionless collapse period ττ∗ of θθ=90° exceeds that of θθ=180°.
  DOI：https://doi.org/10.11159/htff24.199
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85205118673&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85205118673&origin=inward
  DOI ID：10.11159/htff24.199, eISSN：2369-8136, SCOPUS ID：85205118673
• Deformable Sphere Impact On Resting Droplets
  Rafsan Rabbi; Akihito Kiyama; John Allen; Tadd Truscott
  2022年01月18日, ［招待有り］, ［国際誌］, ［国際共著］
  
  Several different rebound behaviors occur when a solid object impacts a resting liquid droplet. High-speed imaging reveals the various droplet rebound phenomena from two spheres with very different elasticities.
  DOI：https://doi.org/10.1115/1.4053571
  DOI ID：10.1115/1.4053571, ISSN：0098-2202, eISSN：1528-901X
• Sphere Falling Onto a Liquid Jet
  Rafsan Rabbi; Akihito Kiyama; Nathan Speirs; Jesse Belden; Tadd Truscott
  2022年01月18日, ［招待有り］, ［国際誌］, ［国際共著］
  
  The history of interfacial fluid dynamics is intertwined with the origins of flash photography from the 'Worthington Jet' of Aurthur Worthington [1] to the 'Milk drop coronets' of Harold Edgerton[2] , with this technique capturing ephemeral fluid impacts in their awe-inspiring beauty. Although camera technology has come far from the days of giant flash bulbs, this elegant technique still provides a uniquely focused window into the fleeting impact events that often seem chaotic in real time, but in the suspended reality of flash-photography are found to be surprisingly well patterned. We apply a similar technique with the help of a laser-controlled photo-receptor in a dark room at night with flashes going off when the light received by the photo-receptor is disturbed. The resultant sequential images of Figure 1 are achieved by the timed release of a 50 mm diameter steel sphere falling from 750 mm plunging through an upward moving Worthington Jet that was created by a 38 mm sphere dropped from 230 mm in line with the second sphere. The jet envelopes the sphere from all sides, with thin water films hugging and moving across the sphere surface continuously until they meet at the sphere apex creating beautiful fluid sheets and ligaments in Figure 2.
  
  
  This image not only captures the beauty of the impact but also reveals a novel mechanism of reducing the impact impulse force of falling objects. The sphere in this particular case experiences an almost 70% reduction in impact force compared to a quiescent pool impact [3, 4].
  DOI：https://doi.org/10.1115/1.4053569
  DOI ID：10.1115/1.4053569, ISSN：0098-2202, eISSN：1528-901X

• マイクロ・ナノ熱工学の進展　　　　　　　　　　　　　　　
  丸山茂夫; 田川義之; 武藤真和; 木山景仁, ［分担執筆］, 第4章第2節

• 加熱油中における水滴の発泡現象に関する実験的検討　　　　　　　　　　　　　　　
  木山景仁; 大塚友晴; 吉田周平; 姜東赫
  日本実験力学会2024年度年次講演会, 2024年09月
  2024年09月 - 2024年09月, 口頭発表（一般）
  共同研究・競争的資金等ID：46268628
• 壁面へと接近する円盤状の物体が壁面との間に生じる気泡について　　　　　　　　　　　　　　　
  木山景仁; 今井渉太; 姜 東赫
  混相流シンポジウム2024, 2024年09月
  2024年09月 - 2024年09月, 口頭発表（一般）
• On the Pinch-off Mechanism of the Deep-Seal Water Entry Cavity near a Rigid Wall　　　　　　　　　　　　　　　
  Hayato Ezumi; Seiya Haranaga; Donghyuk Kang; Tadd T Trusco; Akihito Kiyama
  26th International Congress of Theoretical and Applied Mechanics, 2024年08月
  2024年08月 - 2024年08月, 英語, ポスター発表
  共同研究・競争的資金等ID：46268606
• On the slamming of a Snapping Flexible Shell to Liquid Surface　　　　　　　　　　　　　　　
  Akihito Kiyama; Tomio Goto; Sang Ki Pak; Sunghwan Jung; Donghyuk Kang
  26th International Congress of Theoretical and Applied Mechanics, 2024年08月
  2024年08月 - 2024年08月, 英語, 口頭発表（一般）
• 柔軟材料近傍における水中キャビテーション・衝撃波 に関する実験検討　　　　　　　　　　　　　　　
  木山景仁; 朴翔己; 姜東赫
  2023年度衝撃波シンポジウム, 2024年03月
  2024年03月 - 2024年03月
  共同研究・競争的資金等ID：43444307
• 水中でのスナップ・スルーに伴う流体運動　　　　　　　　　　　　　　　
  木山景仁; Sharon Wang; Sunghwan Jung
  混相流シンポジウム2023, 2023年08月
  2023年08月 - 2023年08月, 日本語, 口頭発表（一般）
• Sound of a handclap: An elastic Helmholtz resonator　　　　　　　　　　　　　　　
  Yicong Wu; Akihito Kiyama; Sunghwan Jung
  American Physical Society (APS) March Meeting 2023, 2023年03月, ［国際会議］, ［国際共著］
  2023年03月 - 2023年03月, 英語
• Sound and cavity dynamics of hand clap　　　　　　　　　　　　　　　
  Akihito Kiyama; Sunghwan Jung
  75th Annual Meeting of the American Physical Society Division of Fluid Dynamics, 2022年11月, ［国際会議］, ［国際共著］
  2022年11月 - 2022年11月, 英語, 口頭発表（一般）
• Listen to your tempura!　　　　　　　　　　　　　　　
  Akihito Kiyama; Rafsan Rabbi; Zhao Pan; Som Dutta; John S Allen; Tadd T Truscott
  74th Annual Meeting of the American Physical Society Division of Fluid Dynamics, 2021年11月, ［国際会議］, ［国際共著］
  2021年11月 - 2021年11月, 英語, 口頭発表（一般）
• Acceleration-induced cavitation of cerebrospinal fluid　　　　　　　　　　　　　　　
  Akihito Kiyama; Jeffery Fonnesbeck; Aaron Olsen; Tadd Truscott
  ASME 2021 FEDSM Fluids Engineering Division Summer Meeting (online), 2021年08月, ［国際会議］, ［国際共著］
  2021年08月 - 2021年08月, 英語, 口頭発表（一般）
  共同研究・競争的資金等ID：33138327
• Reducing the forces of water entry (Keynote lecture)　　　　　　　　　　　　　　　
  Tadd Truscott; Rafsan Rabbi; Nathan Speirs; Akihito Kiyama; Jesse Belden
  ASME 2021 FEDSM Fluids Engineering Division Summer Meeting (online), 2021年08月, ［国際会議］, ［国際共著］
  2021年08月 - 2021年08月, 英語, 口頭発表（基調）
• Consecutive sphere water entry and impact force reduction: post hoc ergo propter hoc!　　　　　　　　　　　　　　　
  Rafsan Rabbi; Nathan Speirs; Akihito Kiyama; Jesse Belden; Tadd Truscott
  73rd Annual Meeting of the American Physical Society Division of Fluid Dynamics (online), 2020年11月, ［国際会議］, ［国際共著］
  2020年11月 - 2020年11月, 英語, 口頭発表（一般）
• Surface-seal changes with impact speeds.　　　　　　　　　　　　　　　
  Akihito Kiyama; Rafsan Rabbi; Nathan Speirs; Jesse Belden; Yoshiyuki Tagawa; Tadd Truscott
  73rd Annual Meeting of the American Physical Society Division of Fluid Dynamics (online), 2020年11月, ［国際会議］, ［国際共著］
  2020年11月 - 2020年11月, 英語, 口頭発表（一般）
• Reducing water entry impact forces by altering cavity dynamics.　　　　　　　　　　　　　　　
  Rafsan Rabbi; Nathan Speirs; Akihito Kiyama; Jesse Belden; Tadd Truscott
  33rd Symposium on Naval Hydrodynamics, 2020年, ［国際会議］, ［国際共著］
  2020年 - 2020年, 英語, 口頭発表（一般）
• Gelatin cavity dynamics in the wake of high-speed solid sphere impact　　　　　　　　　　　　　　　
  Akihito Kiyama; Mohammad M. Mansoor; Nathan B. Speirs; Yoshiyuki Tagawa; Tadd T. Truscott
  72nd Annual Meeting of the APS Division of Fluid Dynamics, 2019年11月, ［国際会議］, ［国際共著］
  2019年11月 - 2019年11月, 英語, 口頭発表（一般）
• On the surface vibration of an impact-induced liquid jet　　　　　　　　　　　　　　　
  Mayuko Ikeda; Hajime Onuki; Akihito Kiyama; Yoshiyuki Tagawa
  International Conference on Advanced Imaging 2019, 2019年, ［国際会議］
  2019年 - 2019年, 英語, ポスター発表
• Jet speed control using bubble-contained hydrogel　　　　　　　　　　　　　　　
  Hajime Onuki; Akihito Kiyama; Yoshiyuki Tagawa
  International Conference on Advanced Imaging 2019, 2019年, ［国際会議］
  2019年 - 2019年, 英語, ポスター発表
• Growth dynamics of surface nanodroplets　　　　　　　　　　　　　　　
  Xuehua Zhang; Brendan Dyett; Akihito Kiyama; Yoshiyuki Tagawa; Detlef Lohse
  71st Annual Meeting of the APS Division of Fluid Dynamics, 2018年11月, ［国際会議］, ［国際共著］
  2018年11月 - 2018年11月, 英語, 口頭発表（一般）
• Control of impact-induced cavitation using bubble-contained PVA gel　　　　　　　　　　　　　　　
  Hajime Onuki; Mao Maeshima; Chihiro Kurihara; Akihito Kiyama; Yoshiyuki Tagawa
  71st Annual Meeting of the APS Division of Fluid Dynamics, 2018年11月, ［国際会議］
  2018年11月 - 2018年11月, 英語, 口頭発表（一般）
• Acceleration-induced cavitation and surrounding pressure in a short liquid column　　　　　　　　　　　　　　　
  Akihito Kiyama; Keisuke Hayasaka; Hiroyuki Nishida; Yoshiyuki Tagawa
  71st Annual Meeting of the APS Division of Fluid Dynamics, 2018年11月, ［国際会議］
  2018年11月 - 2018年11月, 英語, 口頭発表（一般）
• 壁面上の微小気泡を用いたジェット制御　　　　　　　　　　　　　　　
  行貞良介; 木山景仁; ZHANG Xuehua; ZHANG Xuehua; 田川義之
  日本機械学会関東支部総会・講演会講演論文集(CD-ROM), 2018年
  2018年 - 2018年
• 壁面マイクロ/ナノバブルを用いた液体ジェットの増速　　　　　　　　　　　　　　　
  行貞良介; 木山景仁; ZHANG Xuehua; 田川義之
  混相流シンポジウム講演論文集(Web), 2018年
  2018年 - 2018年
• PVAゲルを用いた新規インクジェット射出速度の制御手法　　　　　　　　　　　　　　　
  前嶋麻緒; 大貫甫; 栗原千尋; 木山景仁; 田川義之
  Imaging Conference Japan論文集, 2018年
  2018年 - 2018年
• High-speed measurement of stress fields in soft materials impacted by highly-focused microjets using photoelastic technique　　　　　　　　　　　　　　　
  Yuta Miyazaki; Nanami Endo; Sennosuke Kawamoto; Akihito Kiyama; Yoshiyuki Tagawa
  19th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics, 2018年, ［国際会議］
  2018年 - 2018年, 英語, 口頭発表（一般）
• PVAゲルを用いたキャビテーション制御手法　　　　　　　　　　　　　　　
  前嶋麻緒; 工藤帆乃香; 栗原千尋; 木山景仁; 田川義之
  日本機械学会年次大会講演論文集(CD-ROM), 2017年
  2017年 - 2017年
• 液体急加速時における新しいキャビテーション数の提案　　　　　　　　　　　　　　　
  木山景仁; PAN Zhao; 田川義之; DAILY Jesse; THOMSON Scott; HURD Randy; TRUSCOTT Tadd
  日本機械学会年次大会講演論文集(CD-ROM), 2017年
  2017年 - 2017年
• 加熱平板への高速マイクロ液滴衝突　　　　　　　　　　　　　　　
  藤田裕太; 木山景仁; 田川義之
  混相流シンポジウム講演論文集(CD-ROM), 2017年
  2017年 - 2017年
• 撃力付与時における液中圧力波伝播モデルの提案　　　　　　　　　　　　　　　
  栗原千尋; 木山景仁; 田川義之
  混相流シンポジウム講演論文集(CD-ROM), 2017年
  2017年 - 2017年
• Stress fields in soft material induced by injection of highly-focused microjets　　　　　　　　　　　　　　　
  Yuta Miyazaki; Nanami Endo; Sennosuke Kawamoto; Akihito Kiyama; Yoshiyuki Tagawa
  70th Annual Meeting of the APS Division of Fluid Dynamics, 2017年, ［国際会議］
  2017年 - 2017年, 英語, ポスター発表
• Pressure fluctuation caused by moderate acceleration　　　　　　　　　　　　　　　
  Yoshiyuki Tagawa; Chihiro Kurihara; Akihito Kiyama
  70th Annual Meeting of the APS Division of Fluid Dynamics, 2017年, ［国際会議］
  2017年 - 2017年, 英語, 口頭発表（一般）
• Enhancement of focused jets by using surface microbubbles　　　　　　　　　　　　　　　
  Ryosuke Yukisada; Akihito Kiyama; Xuehua Zhang; Yoshiyuki Tagawa
  70th Annual Meeting of the APS Division of Fluid Dynamics, 2017年, ［国際会議］, ［国際共著］
  2017年 - 2017年, 英語, ポスター発表
• Cavitation onset of an accelerating liquid　　　　　　　　　　　　　　　
  Akihito Kiyama; Zhao Pan; Yoshiyuki Tagawa; David J. Daily; Scott L. Thomson; Randy Hurd; Tadd T. Truscott
  70th Annual Meeting of the APS Division of Fluid Dynamics, 2017年, ［国際会議］, ［国際共著］
  2017年 - 2017年, 英語, 口頭発表（一般）
• High-speed impact of the focused micro liquid jet onto liquid pool　　　　　　　　　　　　　　　
  Akihito Kiyama; Yuta Miyazaki; Zhao Pan; Mujtaba M; Mansoor; Tadd T. Truscott; Yoshiyuki Tagawa
  2nd International Symposium on Image based Metrology, 2017年, ［国際会議］, ［国際共著］
  2017年 - 2017年, 英語, 口頭発表（一般）
• 液体急加速時のキャビテーション発生条件　　　　　　　　　　　　　　　
  栗原千尋; 工藤帆乃香; 木山景仁; 田川義之
  日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2016年
  2016年 - 2016年
• 液中圧力波が集束液体ジェット速度に及ぼす影響　　　　　　　　　　　　　　　
  木山景仁; 早坂啓祐; 田川義之
  混相流シンポジウム講演論文集(CD-ROM), 2016年
  2016年 - 2016年
• Effects of a water hammer and cavitation on the motion of a gas-liquid interface　　　　　　　　　　　　　　　
  Akihito Kiyama; Chihiro Kurihara; Keisuke Hayasaka; Yoshiyuki Tagawa
  24th International Congress of Theoretical and Applied Mechanics, 2016年, ［国際会議］
  2016年 - 2016年, 英語, ポスター発表
• High-speed ethanol micro-droplet impact on a solid surface　　　　　　　　　　　　　　　
  Yuta Fujita; Akihito Kiyama; Yoshiyuki Tagawa
  69th Annual Meeting of the APS Division of Fluid Dynamics, 2016年, ［国際会議］
  2016年 - 2016年, 英語, ポスター発表
• An application of the focused liquid jet: needle free drug injection system　　　　　　　　　　　　　　　
  Akihito Kiyama; Chihiro Katsuta; Sennosuke Kawamoto; Nanami Endo; Akane Tanaka; Yoshiyuki Tagawa
  69th Annual Meeting of the APS Division of Fluid Dynamics, 2016年, ［国際会議］
  2016年 - 2016年, 英語, 口頭発表（一般）
• キャビテーションの発生が先細液体ジェットの速度に与える影響　　　　　　　　　　　　　　　
  木山景仁; 栗原千尋; 田川義之
  日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2015年
  2015年 - 2015年
• Experimental study on the onset of cavitation induced by an impact　　　　　　　　　　　　　　　
  Akihito Kiyama; Chihiro Kurihara; Yoshiyuki Tagawa
  68th Annual Meeting of the APS Division of Fluid Dynamics, 2015年, ［国際会議］
  2015年 - 2015年, 英語, 口頭発表（一般）
• Numerical Study on a focused liquid jet accompanied by gas bubbles　　　　　　　　　　　　　　　
  Akihito Kiyama; Yoshiyuki Tagawa; Wilco Bouwhuis; Devaraj van der Meer; Detlef Lohse
  13th Asian international Conference on Fluid Machinery, 2015年, ［国際会議］, ［国際共著］
  2015年 - 2015年, 英語, 口頭発表（一般）
• 撃力による液体ジェットの速度に関する実験的研究　　　　　　　　　　　　　　　
  木山景仁; 田川義之
  日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2014年
  2014年 - 2014年
• 撃力を用いた集束液体ジェットの増速メカニズムに関する研究　　　　　　　　　　　　　　　
  木山景仁; 野口悠斗; 田川義之
  混相流シンポジウム講演論文集(CD-ROM), 2014年
  2014年 - 2014年
• Study on a liquid jet with cavitation bubbles　　　　　　　　　　　　　　　
  Akihito Kiyama; Yoshiyuki Tagawa
  67th Annual Meeting of the APS Division of Fluid Dynamics, 2014年, ［国際会議］
  2014年 - 2014年, 英語, 口頭発表（一般）
• A focused jet with cavitation bubbles.　　　　　　　　　　　　　　　
  Akihito Kiyama; Yuto Noguchi; Yoshiyuki Tagawa
  10th European Fluid Mechanics Conference, 2014年, ［国際会議］
  2014年 - 2014年, 英語, 口頭発表（一般）
• A focused liquid jet using a pressure impulse　　　　　　　　　　　　　　　
  Akihito Kiyama; Yuto Noguchi; Yoshiyuki Tagawa
  66th Annual Meeting of the APS Division of Fluid Dynamics, 2013年, ［国際会議］
  2013年 - 2013年, 英語, ポスター発表

• 日本混相流学会
• 可視化情報学会
• 日本機械学会

• “Pop” Goes the Toroidal Bubble　　　　　　　　　　　　　　　
  Akihito Kiyama; Sharon Wang; Sunghwan Jung
  2022年11月 - 2022年11月, ［その他］, ［国際共著］
  Gallery of Fluid Motion, 75th APS/DFD Meeting, Indianapolis, Indiana
  DOI ID：10.1103/APS.DFD.2022.GFM.P0037
• Listen to your tempura!　　　　　　　　　　　　　　　
  Akihito Kiyama; Rafsan Rabbi; Zhao Pan; Som Dutta; John S. Allen; Tadd Truscott
  2021年11月 - 2021年11月, ［その他］, ［国際共著］
  Gallery of Fluid Motion, 74th APS/DFD Meeting, Phoenix, Arizona
• Neighbors of water entry　　　　　　　　　　　　　　　
  Akihito Kiyama; Chase Mortensen; Rafsan Rabbi; Tadd Truscott
  2021年11月 - 2021年11月, ［その他］, ［国際共著］
  Gallery of Fluid Motion, 74th APS/DFD Meeting, Phoenix, Arizona
• Deformable Sphere Impact on Resting Droplets　　　　　　　　　　　　　　　
  Rafsan Rabbi; Akihito Kiyama; John Allen; Tadd Truscott
  2021年08月 - 2021年08月, ［その他］, ［国際共著］
  ASME/FEDSM Flow Visualization Competition (Video), 2021
• Sphere Falling Onto a Liquid Jet　　　　　　　　　　　　　　　
  Rafsan Rabbi; Nathan Speirs; Akihito Kiyama; Jesse Belden; Tadd Truscott
  2021年08月 - 2021年08月, ［その他］, ［国際共著］
  ASME/FEDSM Flow Visualization Competition (Poster), 2021
• Viscous droplet umbrellas　　　　　　　　　　　　　　　
  Akihito Kiyama; Rafsan Rabbi; Tadd T Truscott
  2020年11月 - 2020年11月, ［その他］, ［国際共著］
  APS/DFD Gallery of Fluid Motion (Poster), 2020
• The liquid-like response of gels　　　　　　　　　　　　　　　
  Akihito Kiyama; Sennosuke Kawamoto; Mohammad M Mansoor; Nathan Speirs; Randy Hurd; Tadd T Truscott; Yoshiyuki Tagawa
  2017年11月 - 2017年11月, ［その他］, ［国際共著］
  APS/DFD Gallery of Fluid Motion (Poster), 2017
• Droplet spreading: varying viscosity　　　　　　　　　　　　　　　
  Yuta Fujita; Sennosuke Kawamoto; Akhitio Kiyama; Yoshiyuki Tagawa
  2016年11月 - 2016年11月, ［その他］
  APS/DFD Gallery of Fluid Motion (Poster), 2016
• Liquid crowns by water hammer.　　　　　　　　　　　　　　　
  Akihito Kiyama; Yoshiyuki Tagawa
  2015年11月 - 2015年11月, ［その他］
  APS/DFD Gallery of Fluid Motion (Video), 2015
• Cavitation changes ``splash" into ``crown"　　　　　　　　　　　　　　　
  Akihito Kiyama; Yoshiyuki Tagawa
  2014年11月 - 2014年11月, ［その他］
  APS/DFD Gallery of Fluid Motion (Poster), 2014

• 非球形キャビテーション気泡の特異な崩壊メカニズムの解明と機械損傷低減技術の実現　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業, 若手研究, 2024年04月01日 - 2026年03月31日
  木山 景仁, 埼玉大学
  配分額（総額）：4680000, 配分額（直接経費）：3600000, 配分額（間接経費）：1080000
  課題番号：24K17203
  論文ID：48301773, 講演・口頭発表等ID：48134771
• 「温泉中におけるキャビテーション気泡制御で実現する排水配管の長期間保守・洗浄技術」　　　　　　　　　　　　　　　
  公益財団法人イハラサイエンス中野記念財団, 研究助成事業, 2024年04月 - 2025年03月
  研究代表者
• テッポウエビの衝撃波防護機構の解明：生物模倣による高性能ヘルメット開発に向けて　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業, 研究活動スタート支援, 2023年08月 - 2025年03月
  木山 景仁, 埼玉大学
  配分額（総額）：2860000, 配分額（直接経費）：2200000, 配分額（間接経費）：660000
  課題番号：23K19089
  論文ID：42015001, 講演・口頭発表等ID：48134326
• 加熱油中における水蒸気爆発プロセスの解明：エアロゾル発生を解決するスマートセンサの開発に向けて　　　　　　　　　　　　　　　
  日本科学協会, 笹川科学研究助成, 笹川科学研究助成, 2024年04月 - 2025年02月
  埼玉大学, 研究代表者
  配分額（総額）：1050000, 配分額（直接経費）：1050000
  競争的資金, 課題番号：2024-2008
  講演・口頭発表等ID：48134811, 受賞ID：48301765
• 「急加速キャビテーション」の高速度複合計測とその工学的活用基盤の構築　　　　　　　　　　　　　　　
  日本学術振興会, 海外特別研究員, 海外特別研究員, 2020年04月 - 2022年03月
  研究代表者
  講演・口頭発表等ID：33138326
• 撃力による液体ジェットの制御と高粘度液滴を用いた革新的インクジェット技術の開発　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 2016年04月22日 - 2019年03月31日
  木山 景仁, 東京農工大学
  配分額（総額）：3400000, 配分額（直接経費）：3400000
  当該年度は本課題の最終年度であり，これまでに研究成果を挙げてきた撃力による液体ジェットの応用へ向けた研究の実施と，研究成果発表に力点を置いた．
  具体的には，医療機器・生体印刷用途に向けたマイクロジェット研究，および高粘度液体吐出機構開発に関する研究を進めた．まず，マイクロ液体ジェットを用いて，ゼラチンゲル（生体模擬材料）および動物皮膚へ対するマイクロ液体ジェットの衝突・浸透過程の実験的解析を行った．ゼラチンゲルを用いた実験では模擬材料に対する液体浸透過程について，動物皮膚に対する実験では皮膚内部に浸透するに要する条件について，それぞれ知見を得た．上記の結果は，医療機器・生体印刷等，幅広い応用へ向けた基礎的な知見となり得るものと期待される．上記の知見は，査読付き英文学術誌（Journal of Visualization）に論文として発表した．
  また，高粘度液体を吐出するための機構開発のため，撃力により生じるキャビテーション制御手法の実験的検討を行った．液体中に通常生じるキャビテーション(例：Pan & Kiyama, et al., PNAS, 2017)は制御が非常に困難であるのに対し，予め気泡を含有するゲルを系内部に配置することで，その制御を試みた．その結果，ゲルに予め含有される気泡が圧力変動に伴って膨張・収縮することに伴い，通常のキャビテーション気泡と類似の効果が認められ，ジェット射出能が向上した．これは，高粘度液体の吐出機構開発に資するものだと期待される．上記の知見は，査読付き学術雑誌に論文として発表した（前嶋，木山ら，日本画像学会誌，2019）．
  課題番号：16J08521

• Co-Chair: Akihito Kiyama (Cornell) Brian Elbing (Oklahoma State University)　　　　　　　　　　　　　　　
  パネル司会・セッションチェア等
  APS DFD 2022 Session A11: Acoustics: General, 2022年11月20日 - 2022年11月20日
  学会・研究会等
• Manuscript Reviewer　　　　　　　　　　　　　　　
  査読
• Manuscript Reviewer　　　　　　　　　　　　　　　
  査読
  Ocean Engineering
  査読等
• Manuscript Reviewer　　　　　　　　　　　　　　　
  査読
  International Journal of Multiphase Flow
  査読等
• Manuscript Reviewer　　　　　　　　　　　　　　　
  査読
  Physical Review (Letters, Fluids, E)
  査読等
• Manuscript Reviewer　　　　　　　　　　　　　　　
  査読
  Physics of Fluids
  査読等
• Manuscript Reviewer　　　　　　　　　　　　　　　
  査読
  Journal of Fluid Mechanics
  査読等