Transitional behavior of a flow regime in shoaling tsunami boundary layers

Hitoshi Tanaka*, Nguyen Xuan Tinh, Ahmad Sana

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


The transitional flow regime of the bottom boundary layer under hypothetical shoaling tsunamis is investigated in the entire region from the tsunami source to the shallow sea area. In order to calculate the shoaling process of a tsunami, an analytical method based on Green's law and the linear long wave theory are employed, and flow regime criteria for the wave boundary layer proposed by one of the authors are applied. It is found that the bottom boundary layer in a tsunami source area is located in the laminar regime. Subsequently, transition occurs to the smooth turbulence during the shoaling process, with a transition from the smooth to the rough turbulent region in the shallow area. For precise evaluation of bottom friction acting on the sea bed and the resulting energy dissipation beneath the tsunami, it is highly necessary to include such transitional behavior in sea bottom boundary layers.

Original languageEnglish
Article number700
JournalJournal of Marine Science and Engineering
Issue number9
Publication statusPublished - Sept 2020


  • Bottom shear stress
  • Boundary layer
  • Flow regime
  • Tsunami
  • Tsunami shoaling
  • Turbulence model

ASJC Scopus subject areas

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


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