Microscopic theory of Stokes resistance

2020 Fiscal Year Final Research Report

• Project/Area Number: 16K05512
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biological physics/Chemical physics/Soft matter physics
• Research Institution: Niigata University
• Principal Investigator: Akira Yoshimori 新潟大学, 自然科学系, 教授 (90260588)
• Co-Investigator(Kenkyū-buntansha): 秋山 良 九州大学, 理学研究院, 准教授 (60363347)
• Project Period (FY): 2016-04-01 – 2021-03-31
• Keywords: ストークス則 / 拡散 / 佐々の方法

Outline of Final Research Achievements

Stokes' law describes the force exerted on a macroscopic solute from flowing solvent particles using the hydrodynamic equations with a boundary condition on the solute surface. In the present study, the boundary condition is exactly derived from Hamiltonian equations even at a high solvent density, such as a liquid state. It is derived from the large-solute particle limit in regions far from and near the solute particle. From the limit near the solute, the slip boundary condition is always obtained if the solute-solvent particle interaction depends solely on the distance between particles. In addition, the deviation from the slip boundary condition is obtained by perturbation expansion in solute-solvent size ratio.

Free Research Field

化学物理、統計力学

Academic Significance and Societal Importance of the Research Achievements

物体に沿って液体を流すというのは多くの現象に見られ、また応用も多岐にわたる。特に物体が球形の場合は拡散と関係があり、生体内の物質輸送や工学的な応用も高いと考えられる。たとえば、大きい粒子であるにもかかわらず、大きく拡散することができれば、物質の輸送に有利であると考えられる。その鍵を握るのは粒子の表面の境界条件であり、この境界条件と微視的な粒子間相互作用により制御できれば、拡散のしやすさも設計できる。この研究では、境界条件と相互作用の関係を明らかにできた。