• Edson, J. B., C. W. Fairall, P. G. Mestayer, and S. E. Larson, 1991: A study of the inertial-dissipation method for computing air–sea fluxes. J. Geophys. Res.,96, 10 689–10 711.

  • Fleury, M., and R. G. Lueck, 1994: Direct heat flux estimates using a towed vehicle. J. Phys. Oceanogr.,24, 801–818.

    • Crossref
    • Export Citation
  • Gargett, A. E., T. R. Osborn, and P. W. Nasmyth, 1984: Local isotropy and the decay of turbulence in a stratified fluid. J. Fluid Mech.,144, 231–280.

    • Crossref
    • Export Citation
  • Grant, H. L., R. W. Stewart, and A. Moilliet, 1962: Turbulence spectra from a tidal channel. J. Fluid Mech.,12, 241–263.

    • Crossref
    • Export Citation
  • Kolmogrov, A. N., 1941: Local structure in incompressible fluids at very high Reynolds number. Dokl. Akad. Nauk. SSSR,30, 82–85.

  • Lu, Y., and R. G. Lueck, 1999: Using a broadband ADCP in a tidal channel. Part I: Mean flow and shear. J. Atmos. Oceanic Technol.,16, 1556–1567.

  • Lueck, R. G., and Y. Lu, 1998: The logarithmic layer in a tidal channel. Contin. Shelf Res.,17, 1785–1801.

    • Crossref
    • Export Citation
  • ——, D. Huang, D. Newman, and J. Box, 1997: Turbulence measurements with a moored instrument. J Atmos. Oceanic Technol.,14, 143–161.

    • Crossref
    • Export Citation
  • McPhee, M., 1992: Turbulent heat flux in the upper ocean under sea ice. J. Geophys. Res.,97, 5365–5379.

    • Crossref
    • Export Citation
  • Monin, A. S., and A. M. Yaglom, 1975: Statistical Fluid Mechanics. The MIT Press, 874 pp.

  • Ninnis, R., 1984: The spatial transfer function of the airfoil shear probe. Ph.D. thesis, University of British Columbia, 109 pp. [Available from University of British Columbia, Vancouver, BC V6T 1Z4, Canada.].

  • Oakey, N. S., 1982: Determination of the rate of dissipation of turbulent energy from simultaneous temperature and velocity shear microstructure measurements. J. Phys. Oceanogr.,12, 256–271.

    • Crossref
    • Export Citation
  • Osborn, T. R., and R. G. Lueck, 1985: Turbulence measurements from a submarine. J. Phys. Oceanogr.,15, 1502–1520.

    • Crossref
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 128 17 4
PDF Downloads 15 8 6

Dissipation Measurement with a Moored Instrument in a Swift Tidal Channel

View More View Less
  • 1 School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
Restricted access

Abstract

A moored and autonomous instrument that measures velocity and temperature fluctuations in the inertial subrange using shear probes and FP07 thermistors has been deployed in a swift [O(1 m s−1)] tidal channel for eight days. The measured velocity signals are free from body vibrations for frequencies below 16 Hz in flows faster than 0.5 m s−1 and below 8 Hz for slower flows. At lower frequencies, fluctuations of torque on the instrument, due mainly to fluctuations of the ambient current, produce large pitching and rolling motions (≈4° peak) that can easily be reduced by minor mechanical changes. Vibrations at higher frequencies do not scale with flow speed and stem mainly from mechanical structures. The velocity spectrum is free from contamination by body motions between 0.2 and 20 cpm (the inertial subrange), and consistent estimates of the rate of dissipation of kinetic energy are obtained from the spectral levels of vertical and lateral velocity fluctuations within this range.

Corresponding author address: Rolf Lueck, School of Earth and Ocean Sciences, University of Victoria, P.O. Box 1700, Victoria, BC V8W 2Y2, Canada.

Email: rlueck@uvic.ca

Abstract

A moored and autonomous instrument that measures velocity and temperature fluctuations in the inertial subrange using shear probes and FP07 thermistors has been deployed in a swift [O(1 m s−1)] tidal channel for eight days. The measured velocity signals are free from body vibrations for frequencies below 16 Hz in flows faster than 0.5 m s−1 and below 8 Hz for slower flows. At lower frequencies, fluctuations of torque on the instrument, due mainly to fluctuations of the ambient current, produce large pitching and rolling motions (≈4° peak) that can easily be reduced by minor mechanical changes. Vibrations at higher frequencies do not scale with flow speed and stem mainly from mechanical structures. The velocity spectrum is free from contamination by body motions between 0.2 and 20 cpm (the inertial subrange), and consistent estimates of the rate of dissipation of kinetic energy are obtained from the spectral levels of vertical and lateral velocity fluctuations within this range.

Corresponding author address: Rolf Lueck, School of Earth and Ocean Sciences, University of Victoria, P.O. Box 1700, Victoria, BC V8W 2Y2, Canada.

Email: rlueck@uvic.ca

Save