BED INSTABILITY GENERATED BY TURBIDITY CURRENTS

• PEN Sytharith

  北海道大学 大学院工学院

• IZUMI Norihiro

  北海道大学 大学院工学研究院

• HAGISAWA Sakura

  NEXCO東日本

Bibliographic Information

Other Title

• 混濁流によって発生する底面不安定現象

Abstract

 A turbidity current is a density flow the driving force of which is a density increase due to suspended sediment contained in water. In the case of saline or thermal density flows, salt concentration or temperature as a driving force is diluted due to diffusion as it flows down, and therefore, it cannot move long distance. In the case of turbidity currents however, it has been found that the lower layer with high sediment concentration has an equilibrium state because the diffusion is balanced with the settling of suspended sediment¹⁾. In this paper, we assume that the high concentrated lower layer is in an equilibrium condition, and performed linear stability analysis of bed instability due to turbidity currents by applying a simple mixing length turbulent model. It is found from the analysis that the flat bed becomes unstable to evolve into the bed covered with bedwaves in the range of the densimetric Froude number larger than approximately 0.4.

Journal

• Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering)

  Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 74 (4), I_1105-I_1110, 2018

  Japan Society of Civil Engineers

Keywords

• turbidity current
• bed instability
• mixing length hypothesis
• linear stability analysis
• bedwave

Details

• CRID: 1390564238096679296
• NII Article ID: 130007628139
• DOI: 10.2208/jscejhe.74.i_1105
• ISSN: 2185467X
• Web Site: https://www.jstage.jst.go.jp/article/jscejhe/74/4/74_I_1105/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed