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Ocean Physics

Ocean Physics includes all the ways in which the marine environment can be understood using physics.

Our research group is active in Oceanography (secondary currents in curved flows, ocean waves generated by atmospheric disturbances), Numerical Modelling (interpolation of Acoustic Doppler Current Profile (ADCP) data, modeling estuarine flow) and Applied Ocean Physics (design of tidal turbine farms).

People          TopButton

  • Associate Professor Ross Vennell, Senior Lecturer
    physical oceanography/ocean physics, tidal physics, oceanography of estuaries, straits and channels, headland and island eddies
  • Cerys Bailey, PhD candidate
    Two-layer flow, curvature and mixing in the Taieri River
  • Alice Harang
  • Malcolm Smeaton
  • Vaugn Weatherall
  • Rob Smith, PhD candidate
    Where is the subtropical front?

Research Projects       TopButton

A scaling law for a renewable energy resource: Is Giga-Watt output from tidal turbine farms realistic?
Principal Investigator: Ross Vennell
Supported by the Marsden Fund 2013-2016
Power from turbines in strong tidal currents will contribute to the increasing demand for renewable energy. Currently operating tidal turbines are producing around 1 Mega-Watt of energy. Realising the Giga-Watt potential of large tidal channels such as Cook Strait could contribute significantly to meeting the NZ Government’s target of increasing electricity generation from renewable sources from 73% in 2010 to 90% by 2025. To do this, tidal turbine farms must scale up from a few turbines, to hundreds of turbines. Unlike wind turbine farms, production from large tidal turbine farms does not increase in direct proportion to the number of turbines, because power extraction slows flows along the entire channel. This complex interaction between power extraction and flow speeds has meant that our understanding of how power production increases as a turbine farm grows is extremely limited. The proposed work uses analytical and computational techniques to develop a fundamental scaling law to underpin the relationship between power production and farm size. This scaling law would constitute a significant step towards addressing a core question for tidal current power: is it realistic to meet a significant fraction of our future energy needs by increasing the scale of tidal turbine farms?
Link to News article:
For more information about energy-related research at Otago, see: Otago Energy Research Centre:

Opportunities    TopButton

Otago has PhD Scholarships available to well qualified students in:

  • Optimising tidal turbine farms and the assessment of the tidal current resource
  • Tidal dynamics and secondary flows in the coastal ocean

Selected Recent Publications       TopButton

  • Divett, T., Vennell, R., & Stevens, C. (2013). Optimization of multiple turbine arrays in a channel with tidally reversing flow by numerical modelling with adaptive mesh. Philosophical Transactions of the Royal Society A, 371(1985), 20120251.
  • Vennell, R. (2013). Exceeding the Betz limit with tidal turbines. Renewable Energy, 55, 277-285.
  • Vennell, R. (2012). Realizing the potential of tidal currents and the efficiency of turbine farms in a channel. Renewable Energy, 47, 95-102.
  • Thiebaut, S., & Vennell, R. (2011). Resonance of long waves generated by storms obliquely crossing shelf topography in a rotating ocean. Journal of Fluid Mechanics, 682, 261-288.
  • Vennell, R. (2011). Tuning tidal turbines in-concert to maximise farm efficiency. Journal of Fluid Mechanics, 671, 587-604.
  • Vennell, R. (2010). Tuning turbines in a tidal channel. Journal of Fluid Mechanics, 663, 253-267.
  • Thiebaut, S., & Vennell, R. (2010). Observation of a fast continental shelf wave generated by a storm impacting Newfoundland using wavelet and cross-wavelet analyses. Journal of Physical Oceanography, 40(2), 417-428.
  • Vennell, R., & Old, C. (2007). High-resolution observations of the intensity of secondary circulation along a curved tidal channel. Journal of Geophysical Research, 112, C11008
  • Vennell, R., Pease, D., & Wilson, B. (2006). Wave drag on human swimmers. Journal of Biomechanics, 39, 664-671.
  • Albrecht, N., Vennell, R., Williams, M., Stevens, C., Langhorne, P., Leonard, G., & Haskell, T. (2006). Observation of sub-inertial internal tides in McMurdo Sound, Antarctica. Geophysical Research Letters, 33, L24606