Cooperative effect of diffusion and convection

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K14370
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13010:Mathematical physics and fundamental theory of condensed matter physics-related
• Research Institution: Kobe University (2021-2023); Tohoku University (2020)
• Principal Investigator: Koyano Yuki 神戸大学, 人間発達環境学研究科, 助教 (50849643)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 移流拡散方程式 / フォッカー・プランク方程式 / 移流 / 拡散 / 異常拡散

Outline of Final Research Achievements

Convection and diffusion are fundamental processes in regard to fluid mixing. The two dynamics, convection and diffusion, usually have different spatial and temporal scales, and thus they can be considered separately.
However, it has been revealed by the experiments that the cooperative effect of convection and diffusion can cause nontrivial diffusion enhancement.
In this study, such cooperative effects were precisely investigated. We numerically found that anisotropic diffusion and net shift as well as diffusion enhancement were observed under a reciprocal flow. Such anomalous diffusion and convection were theoretically explained by the discrete Fokker-Planck equation of the Langevin dynamics.

Free Research Field

非線形物理学

Academic Significance and Societal Importance of the Research Achievements

移流と拡散が協働する現象はサブミリメートル以下のスケールで重要だと考えられる。近年、浮遊させた液滴を変形・合体させる技術や、マイクロ流路内での溶液混合など、ミクロなスケールで流体を操作する工業的技術が発展を遂げている。本研究はそれらに基礎的な知見を与えることが期待される。また、細胞内には形状が変形するタンパク質が多数存在するが、そういったアクティブな要素が変形運動を続ける環境下での物質拡散に対しても重要な知見を与える可能性がある。