Tsunami Damping due to Bottom Friction Considering Flow Regime Transition and Depth-Limitation in a Boundary Layer

Hitoshi Tanaka*, Nguyen Xuan Tinh, Ahmad Sana

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


According to recent investigations on bottom boundary layer development under tsunami, a wave boundary can be observed even at the water depth of 10 m, rather than a steady flow type boundary layer. Moreover, it has been surprisingly reported that the tsunami boundary layer remains laminar in the deep-sea area. For this reason, the bottom boundary layer under tsunami experiences two transitional processes during the wave shoaling: (1) flow regime transition in a wave-motion boundary layer from laminar to the turbulent regime, and (2) transition from non-depth-limited (wave boundary layer) to depth-limited boundary layer (steady flow boundary layer). In the present study, the influence of these two transition processes on tsunami wave height damping has been investigated using a wave energy flux model. Moreover, a difference of calculation results by using the conventional steady flow friction coefficient was clarified.

Original languageEnglish
Article number1433
JournalJournal of Marine Science and Engineering
Issue number10
Publication statusPublished - Oct 5 2022


  • bottom friction
  • depth-limitation
  • flow regime
  • tsunami damping
  • wave boundary layer

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Water Science and Technology
  • Ocean Engineering

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