New Bedform Phase Diagrams and Discriminant Functions for Formative Conditions of Bedforms in Open-Channel Flows

• Ohata, Koji

  Department of Geology and Mineralogy, Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University

• Naruse, Hajime

  Department of Geology and Mineralogy, Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University

• Yokokawa, Miwa

  Faculty of Information Science and Technology, Osaka Institute of Technology

• Viparelli, Enrica

  Department of Civil and Environmental Engineering, University of South Carolina

Bibliographic Information

Other Title

• New Bedform Phase Diagrams and Discriminant Functions for Formative Conditions of Bedforms in Open‐Channel Flows

Abstract

Understanding of the formative conditions of fluvial bedforms is significant for both river management and geological studies. Diagrams showing bedform stability conditions have been widely used for the analyses of sedimentary structures. However, the use of discriminants to determine the boundaries of different bedforms regimes has not yet been explored. In this study, we use discriminant functions to describe formative conditions for a range of fluvial bedforms in a 3-D dimensionless parametric space. We do this by means of discriminant analysis using the Mahalanobis distance. We analyzed 3, 793 available laboratory and field data and used these to produce new bedform phase diagrams. These diagrams employ three dimensionless parameters representing properties of flow hydraulics and sediment particles as their axes. The discriminant functions for bedform regimes proposed herein are quadratic functions of three dimensionless parameters and are expressed as curved surfaces in 3-D space. These empirical functions can be used to estimate paleoflow velocities from sedimentary structures. As an example of the reconstruction of hydraulic conditions, we calculated the paleoflow velocity of the 2011 Tohoku-Oki tsunami backwash flow from the sedimentary structures of the tsunami deposit. In so doing, we successfully reconstructed reasonable values of the paleoflow velocities.

Journal

• Journal of Geophysical Research: Earth Surface

  Journal of Geophysical Research: Earth Surface 122 (11), 2139-2158, 2017-11

  Wiley-Blackwell

Keywords

• bedforms
• bedform phase diagram
• discriminant analysis
• discriminant functions
• paleoflow conditions

Details

• CRID: 1050564285805434880
• NII Article ID: 120006373945
• ISSN: 21699003
• ISSN: 21699011
• DOI: 10.1002/2017jf004290
• HANDLE: 2433/228345
• Web Site: https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2017JF004290
• Web Site: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017JF004290
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN