LES study of near-seabed tide-induced turbulence in the East China Sea

Yoshinobu Wakata, Takahiro Endo, Yutaka Yoshikawa

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Near-seabed turbulent properties observed in the East China Sea were investigated using a large eddy simulation (LES) model. Tidal forcing estimated from the observed tidal current is imposed to the LES model assuming a flat seabed. Turbulence stirred by tidal currents near the seabed is simulated and compared to observed turbulence. The observed tide is dominated by the M2 constituent. The energy dissipation rate evolves with a quarter-day period near the seabed, whereas the dissipation rate evolves with a diurnal period in the upper part of the boundary layer. Salinity also oscillates diurnally. Thickness of the boundary layer related to K1 is thicker than that of M2. Orientation of the major axis of M2 in the tidal ellipse does not change downward, but that of K1 rotates counterclockwise. The vertical structure difference of two constituents is attributable to the observation site latitude, which is approximately the critical latitude of K1. All of these features are simulated in the LES model. Particularly, results show that the interference of M2 and K1 induces diurnal variation of the turbulent dissipation rate in the upper part of the boundary layer through the turbulent energy production rate controlled by the vertical shear. A hypothetical simulation without horizontal advection demonstrate that this process can contribute more to the diurnal variation in the upper part of the boundary layer than stratification stability control owing to salinity advection through tidal straining.

Original languageEnglish
Pages (from-to)21-31
Number of pages11
JournalContinental Shelf Research
Volume145
DOIs
Publication statusPublished - Aug 1 2017

Fingerprint

East China Sea
large eddy simulation
tides
simulation models
tide
boundary layer
turbulence
diurnal variation
tidal current
salinity
dissipation
advection
energy
shears
ellipse
energy dissipation
stratification
sea
rate
simulation

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Aquatic Science
  • Geology

Cite this

LES study of near-seabed tide-induced turbulence in the East China Sea. / Wakata, Yoshinobu; Endo, Takahiro; Yoshikawa, Yutaka.

In: Continental Shelf Research, Vol. 145, 01.08.2017, p. 21-31.

Research output: Contribution to journalArticle

Wakata, Yoshinobu ; Endo, Takahiro ; Yoshikawa, Yutaka. / LES study of near-seabed tide-induced turbulence in the East China Sea. In: Continental Shelf Research. 2017 ; Vol. 145. pp. 21-31.
@article{fbef85f62f3f4009adf033bb55ab5cae,
title = "LES study of near-seabed tide-induced turbulence in the East China Sea",
abstract = "Near-seabed turbulent properties observed in the East China Sea were investigated using a large eddy simulation (LES) model. Tidal forcing estimated from the observed tidal current is imposed to the LES model assuming a flat seabed. Turbulence stirred by tidal currents near the seabed is simulated and compared to observed turbulence. The observed tide is dominated by the M2 constituent. The energy dissipation rate evolves with a quarter-day period near the seabed, whereas the dissipation rate evolves with a diurnal period in the upper part of the boundary layer. Salinity also oscillates diurnally. Thickness of the boundary layer related to K1 is thicker than that of M2. Orientation of the major axis of M2 in the tidal ellipse does not change downward, but that of K1 rotates counterclockwise. The vertical structure difference of two constituents is attributable to the observation site latitude, which is approximately the critical latitude of K1. All of these features are simulated in the LES model. Particularly, results show that the interference of M2 and K1 induces diurnal variation of the turbulent dissipation rate in the upper part of the boundary layer through the turbulent energy production rate controlled by the vertical shear. A hypothetical simulation without horizontal advection demonstrate that this process can contribute more to the diurnal variation in the upper part of the boundary layer than stratification stability control owing to salinity advection through tidal straining.",
author = "Yoshinobu Wakata and Takahiro Endo and Yutaka Yoshikawa",
year = "2017",
month = "8",
day = "1",
doi = "10.1016/j.csr.2017.06.020",
language = "English",
volume = "145",
pages = "21--31",
journal = "Continental Shelf Research",
issn = "0278-4343",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - LES study of near-seabed tide-induced turbulence in the East China Sea

AU - Wakata, Yoshinobu

AU - Endo, Takahiro

AU - Yoshikawa, Yutaka

PY - 2017/8/1

Y1 - 2017/8/1

N2 - Near-seabed turbulent properties observed in the East China Sea were investigated using a large eddy simulation (LES) model. Tidal forcing estimated from the observed tidal current is imposed to the LES model assuming a flat seabed. Turbulence stirred by tidal currents near the seabed is simulated and compared to observed turbulence. The observed tide is dominated by the M2 constituent. The energy dissipation rate evolves with a quarter-day period near the seabed, whereas the dissipation rate evolves with a diurnal period in the upper part of the boundary layer. Salinity also oscillates diurnally. Thickness of the boundary layer related to K1 is thicker than that of M2. Orientation of the major axis of M2 in the tidal ellipse does not change downward, but that of K1 rotates counterclockwise. The vertical structure difference of two constituents is attributable to the observation site latitude, which is approximately the critical latitude of K1. All of these features are simulated in the LES model. Particularly, results show that the interference of M2 and K1 induces diurnal variation of the turbulent dissipation rate in the upper part of the boundary layer through the turbulent energy production rate controlled by the vertical shear. A hypothetical simulation without horizontal advection demonstrate that this process can contribute more to the diurnal variation in the upper part of the boundary layer than stratification stability control owing to salinity advection through tidal straining.

AB - Near-seabed turbulent properties observed in the East China Sea were investigated using a large eddy simulation (LES) model. Tidal forcing estimated from the observed tidal current is imposed to the LES model assuming a flat seabed. Turbulence stirred by tidal currents near the seabed is simulated and compared to observed turbulence. The observed tide is dominated by the M2 constituent. The energy dissipation rate evolves with a quarter-day period near the seabed, whereas the dissipation rate evolves with a diurnal period in the upper part of the boundary layer. Salinity also oscillates diurnally. Thickness of the boundary layer related to K1 is thicker than that of M2. Orientation of the major axis of M2 in the tidal ellipse does not change downward, but that of K1 rotates counterclockwise. The vertical structure difference of two constituents is attributable to the observation site latitude, which is approximately the critical latitude of K1. All of these features are simulated in the LES model. Particularly, results show that the interference of M2 and K1 induces diurnal variation of the turbulent dissipation rate in the upper part of the boundary layer through the turbulent energy production rate controlled by the vertical shear. A hypothetical simulation without horizontal advection demonstrate that this process can contribute more to the diurnal variation in the upper part of the boundary layer than stratification stability control owing to salinity advection through tidal straining.

UR - http://www.scopus.com/inward/record.url?scp=85025079252&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85025079252&partnerID=8YFLogxK

U2 - 10.1016/j.csr.2017.06.020

DO - 10.1016/j.csr.2017.06.020

M3 - Article

AN - SCOPUS:85025079252

VL - 145

SP - 21

EP - 31

JO - Continental Shelf Research

JF - Continental Shelf Research

SN - 0278-4343

ER -