日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 A (大気水圏科学) » A-GE 地質環境・土壌環境

[A-GE31] New Roles of Soil Science for Extraterrestrials

2019年5月28日(火) 13:45 〜 15:15 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:登尾 浩助(Meiji University)、溝口 勝(東京大学大学院農学生命科学研究科)

[AGE31-P04] Challenges to measuring of the contact angle and the surface tension of water under reduced gravity

*長沼 菜摘1佐藤 直人1野川 健人1丸尾 裕一1登尾 浩助2 (1.明治大学大学院農学研究科、2.明治大学農学部)

キーワード:capillary pressure、contact angle、surface tension、reduced gravity、maximum bubble method

Matric potential gradient is one of the driving forces of water movement in porous media. It has been reported that water movement in porous media under microgravity was slower than that under 1G, and hydraulic characteristic curve changed. Therefore, there is a possibility that the matric potential changes under reduced gravity. Capillary pressure is the main factor of dominating the matric potential value in porous media with a relatively large pore size. In this study we investigated the dependence of capillary force on gravity. Capillary forces are governed by the surface tension and contact angle that the liquid makes with the solid surfaces. We measured the contact angle of droplets on glass plate under microgravity condition to reveal the dependence of the contact angle on gravity. For large droplets, the contact angle under microgravity was larger than that under 1G, but the difference in contact angle between 1G and µG reduced with smaller droplets. We also conducted parabolic experiments to measure the surface tension of water under reduced gravity (µG, 1/6G, 1/3G, 1G). The maximum bubble pressure method which is one of the methods measuring surface tension was used. The bubble pressure greatly changed due to dynamically change of the inboard air pressure during parabolic flight. Evaluation of the surface tension by removing air pressure and hydraulic pressure from bubble pressure will be discussed.