P03
CBEF を用いた低重力環境下液体挙動に関する ISS 軌道実験
-重力加速度が密閉容器内スロッシング現象に与える影響On-orbit Experiments via CBEF aboard the ISS onSloshing Phenomena under Normal and Reduced
Gravity Conditions
草野素晴 1, 村上岳 1, 古市彦乃 2, 黒瀬築 2, 桜井誠人 3, 坂本佑介 3, 神吉誠志 3, 上野一郎 2Motoharu KUSANO1, Gaku MURAKAMI1, Hikono FURUICH2, Kizuku KUROSE2, Masato SAKURAI3,Yusuke SAKAMOTO3, Seiji KAMIYOSHI3, Ichiro UENO2
東京理科大学大学院，Tokyo University of Science
東京理科大学，Tokyo University of Science3
宇宙航空研究開発機構，Japan Aerospace Exploration Agency
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It is necessary to investigate and develop for future manned space exploration on the Moon and Mars. In
particular, elucidation and control of gas-liquid two-phase flow behavior under microgravity and low gravity
conditions are important and critical for liquid transport and gas-liquid separation in space. Whereas sloshingphenomena is one of the important problems in fluid mechanics and fluid engineering and have been studied
under normal and microgravity1,2), the knowledge of sloshing phenomena under low gravity is still fatally
limited. The Japan Aerospace Exploration Agency (JAXA) conducted a series of rotationally swinging
experiments under low gravity on the International Space Station (ISS) in 2022 using the Cell Biology
Experiment Facility (CBEF). Prior to the space experiments, we have conducted ground-based experiments
and developed a simulation model for prediction of the liquid motion with free surface3). In this study, weanalyze the data from the space experiments in detail and investigate the effect of gravitational accelerationand oscillation frequency on the sloshing phenomena. Additionally, we predict the liquid level amplitudeunder low gravity condition using the simulation model and compare the results with the experiments.
Figure 1 shows the small rectangular vessel for (a)on–orbit experiment and (b)numerical simulation. The
sealed vessel is filled with liquid and air. The vessel is rotated side by side around its axis of rotation, whichis parallel to the z axis through the centered point in the figure. The maximum angle of rotation 𝜃max is 10degrees. The direction of gravity was set to be in the negative direction of the y-axis. Gravitational acceleration
was varied under three conditions: normal (on the ground) (G), on the Moon (G/6), and on the Mars (G/3).
The vessel was rotated while varying the oscillation frequency, and the motion of the liquid with the freesurface were observed. The interFoam solver of OpenFOAM is used as the numerical simulation solver, whichsolves gas-liquid two-phase flows using the Volume of Fluid (VOF) method. A moving mesh function isapplied to reproduce the reciprocating rotational motion of the vessel around its axis.
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Figure 2 shows the normalized liquid-level amplitude of free surface 𝐴/𝐿 against the normalized oscillation
frequency 𝑓/𝑓1st under the normal and moon gravity acceleration conditions, respectively. Where f1st is theprimary resonance frequency for laterally oscillating rectangular vessel. The results for the moon gravity areplotted up to the higher 𝑓/𝑓1st than that for the normal one because f1st decreases with gravitationalacceleration. Distinct tendencies exhibit depending on variations in gravitational acceleration. When 𝑓/𝑓1st is
greater than 1.0, the liquid-level amplitude increases and reaches the peak, and then decreases under thenormal gravity. Whereas no significant decrease is observed, and the liquid-level amplitude gradually
increases at higher frequencies under the moon gravity. In the presentation, we will discuss the effect ofgravitational acceleration on the liquid behaviors in detail.
(a)(b)
BaffleBaffleGas (air)yxoInterface

Liquid (water)oY

Gas (air)yInterfaceyx

Liquid (water)

zo’oθ

x
X

Figure 1. Rectangular vessels for sloshing test (a) on-orbit experiment and (b) numerical model.

Figure 2. Normalized liquid-level amplitude of free surface 𝐴/𝐿 against normalized oscillation
frequency 𝑓/𝑓1st under the normal and moon gravity acceleration conditions obtained by on-orbit
experiment.

References
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W. J. Yang, T. T. Zhang, C. Li, S. M. Li and X. H. Xu: Journal of Aeronautics, 28(3) (2019), 1527,
DOI: 10.29252/jafm.12.05.29677
S. Kaneko, T. Ishiyama and T. Sawada: Journal of Physics: Conference Series, 412(2013), 012018,
DOI: 10.1088/1742-6596/412/012018
S. Chino, G. Murakami, M. Kusano, K. Kurose, Y. Sakamoto, K. Kazuya, M. Sakamoto, M. Sakurai and I. Ueno:
International Journal of Microgravity Science and Application, 40(2) (2023), 400202,
DOI: https://doi.org/10.15011/jasma.40.400202© 2023 by the authors. Submitted for possible open access publication under theterms and conditions of the Creative Commons Attribution (CC BY) license(http://creativecommons.org/li censes/by/4.0/).
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