Reynolds stress and turbulence estimates in bottom boundary layer of Fall of Warness

Emmanuel Osalusi, Jonathan Charles Side, Robert Ewan Harris

Research output: Contribution to journalArticle

Abstract

A broadband acoustic Doppler current profiler (ADCP) moored on the seabed at 42 m depth has been used to observe the mean and turbulent flow components in the tidally energetic Fall of Warness channel over two tidal cycles. The Reynolds stress has been estimated from the difference in variance between the along-beam velocities of opposing acoustic beams. Near bed stress at 2.63 m above seabed (mab) exceeds 7.5 Pa at the time of mean flow (speed of ~ 1.3 m s- 1) while the ebb stresses are limited to ~ 3.31 Pa during the peak ebb, mean, flow of ~ 1.3 m s- 1. The production of turbulent kinetic energy (TKE), P was found to be negative below 2 × 10- 9 W m- 3 and up to 6 × 10- 4 W m- 3 was estimated during flood flows and decreasing to 3 × 10- 4 W m- 3. The TKE dissipation rate e was estimated by inertial dissipation method (IDM) with the greatest value of 2.43 × 10- 2 W m- 3 observed near the seabed around maximum ebb, falling to 5.75 × 10- 5 W m- 3 around slack water. The comparison between P and e was performed by calculating individual ratios of P corresponding to e using a bootstrap resampling technique. The study shows that the ratio e/P averaged over whole flood and ebb were found to be ~ 0.4138 and ~ 0.4177, respectively, indicating that production exceeded dissipation. The uncertainties in Reynolds stress estimates due to instrument noise were found to be 3 × 10- 4 Pa while 4.52 × 10- 2 Pa can be attributed to the uncertainties due to the increase in the flow-related component. © 2009 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)412-421
Number of pages10
JournalInternational Communications in Heat and Mass Transfer
Volume36
Issue number5
DOIs
Publication statusPublished - May 2009

Fingerprint

benthic boundary layer
turbulence
kinetic energy
dissipation
bottom stress
Acoustic Doppler Current Profiler
tidal cycle
energy dissipation
turbulent flow
acoustics
energetics
water

Keywords

  • ADCP
  • Reynolds stress
  • TKE production
  • Turbulent kinetic energy

Cite this

Osalusi, Emmanuel ; Side, Jonathan Charles ; Harris, Robert Ewan. / Reynolds stress and turbulence estimates in bottom boundary layer of Fall of Warness. In: International Communications in Heat and Mass Transfer. 2009 ; Vol. 36, No. 5. pp. 412-421.
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Reynolds stress and turbulence estimates in bottom boundary layer of Fall of Warness. / Osalusi, Emmanuel; Side, Jonathan Charles; Harris, Robert Ewan.

In: International Communications in Heat and Mass Transfer, Vol. 36, No. 5, 05.2009, p. 412-421.

Research output: Contribution to journalArticle

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AU - Side, Jonathan Charles

AU - Harris, Robert Ewan

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