Image by vivek kumar
Image by vivek kumar

Image by Thomas Kelley
Image by Thomas Kelley

Humpback whale
Humpback whale

Image by vivek kumar
Image by vivek kumar

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Humpback Whale
  • Giant marine mammal, 12~16m long
  • Distinctive body shape, with unusually long fins
Bubble net hunt:
1. A group of them swim circularly to drive tons of fish into a small circular zone;
2. Produce bubbles as a bubble net to prevent the fish from escaping;
3. All together swallow tones of fish

Unusually long fins with leading-edge tubercles?

Apply tubercle technology to a hydrofoil 

  • 3D printed leading-edge sections
    • 4 wavy leading-edge sections

    • 4 smooth leading-edge sections

  • Support base part

    • CNC machined

    • Carbon fibre reinforced plastic

  • The performance of the hydrofoil can be dramatically enhanced by the tubercles

  • The lift coefficients were increased greatly

  • Foil with the shortest tubercle application length (1/4 of the span) at tip region overall displayed the best performance

  • A strong tip vortex cavitation can be produced by “0000”, smooth leading, while no cavitation can be observed under the same condition of “1111”.
  • Contra-rotating vortex fence can be produced by tubercles to prevent the spanwise flow.

  • Tip loss or three dimensional effect can be greatly lowered.

This concept is currently being applied to the following marine devices:
  • Tidal Turbine
  • Open Propeller
  • Control Surfaces (e.g. Rudder)
  • Propeller Duct
Cavitating tubercle turbine
Cavitating tubercle turbine

Duct
Duct

Tidal turbine
Tidal turbine

Cavitating tubercle turbine
Cavitating tubercle turbine

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Featured Research Outcomes:
  1. Arrangements, Duct Arrangements and Methods Thereof, UK Patent Application, 2011399.9
  2. Shi, W.*, M. Atlar, R. Norman, S. Day and B. Aktas (2019). "Effect of waves on the leading-edge undulated tidal turbines." Renewable Energy 131: 435-447.
  3. Shi, W.*, M. Atlar and R. Norman (2017). "Detailed flow measurement of the field around tidal turbines with and without biomimetic leading-edge tubercles." Renewable Energy 111(111): 688-707.
  4. Shi, W.*, M. Atlar, R. Norman, B. Aktas and S. Turkmen (2016). "Numerical optimization and experimental validation for a tidal turbine blade with leading-edge tubercles." Renewable Energy 96: 42-55.
  5. Shi, W.*, M. Atlar, R. Rosli, B. Aktas and R. Norman (2016). "Cavitation observations and noise measurements of horizontal axis tidal turbines with biomimetic blade leading-edge designs." Ocean Engineering 121: 143-155.
  6. Shi, W.*, R. Rosli, M. Atlar, R. Norman, D. Wang and W. Yang (2016). "Hydrodynamic performance evaluation of a tidal turbine with leading-edge tubercles." Ocean Engineering 117: 246-253.