Searching for the mechanism of river channel network formation using the maximum entropy production principle and challenge to mathematical morphology

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K18740
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 22:Civil engineering and related fields
• Research Institution: Fukushima University
• Principal Investigator: YOKOO Yoshiyuki 福島大学, 共生システム理工学類, 教授 (90398503)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 河道網 / 降雨流出氾濫モデル / 河床波 / 反応 / 移流 / 拡散

Outline of Final Research Achievements

The present study aimed at clarifying the possibility of the formation of a tree-structured river channel network, tree branches, and natural striped and mottled patterns according to the maximum entropy production (MEP) principle. First, the frictional energy loss in the river channel and on the slope connected to the river was calculated using a rainfall-runoff inundation model. The results showed that the channel and slope tended to be distributed so that the total frictional energy loss was minimized, indicating that the river channel network may be formed according to the MEP principle. Next, using a riverbed wave model based on a reaction-advection-diffusion equation, it was shown that riverbed waves are formed when the reaction, advection, and diffusion phenomena satisfy certain conditions, indicating that riverbed waves may also be formed according to the MEP principle.

Free Research Field

流域水文学

Academic Significance and Societal Importance of the Research Achievements

従来，河道網や河床波の形成が，エントロピー生成最大化（MEP）原理に支配されている可能性を実践的に調べた研究はなかったが，本研究はこれに初めて取り組んだ．これにより，河道網や河床波がなぜ形成されるのか，という高次の謎に迫ることができた．今後，自然界や人間社会で共通して見られる模様が形成される要因がMEP原理によって明らかになる可能性がある．そのような成果は，従来の学問分野を超越した新しい学問領域を創出し，それらの応用が我々の社会や生活を革新的に効率化できる可能性がある．