Remote acoustic measurements of turbulence in high-speed flows with application to in-stream tidal turbine development: The Vectron project
The overall goals of the project are: (I) to improve the knowledge and understanding of turbulence in high flow
tidal channels; and (II) to reduce the high uncertainty surrounding the effects of turbulence on in-stream
turbines. Specific main objectives are: (1) estimates - with error bounds - of higher-order turbulence statistics,
with an emphasis on the statistics of extremes; (2) quantitative comparisons between model-predicted
turbulence fields and measurements; (3) quantifying the turbulent contribution to Doppler noise levels in high
flow environments; and (4) improved assumptions concerning the turbulence metrics used by in-stream turbine
Our approach combines state-of-the-art acoustic Doppler technique with advanced computational fluid
dynamics modelling. A newly-developed acoustic Doppler system - the Vectron - will be used to make the
necessary measurements in Minas Passage in the Bay of Fundy - arguably the site with the greatest tidal power
potential worldwide. The Vectron represents a major advance in flow measurement technology, incorporating
wide-baseline convergent-beam geometry with a new pulse-coherent processing algorithm to achieve
co-located, high sampling rate, turbulence-resolving velocity measurements at or near turbine "hub height".
Turbulence-resolving Detached Eddy Simulation (DES) models employing state-of-the-art Graphical
Processing Unit (GPU) techniques will be implemented for the turbine berth area in Minas Passage, with
boundary conditions provided by a tidal circulation model encompassing the Bay of Fundy/Gulf of Maine.
The significance of the proposed research is two-fold. (1) Fundamental: The combined measurement and
modelling program will provide new knowledge, insight and understanding of turbulence in high flow tidal
channels. (2) Applied: By quantifying the recurrence frequencies of extreme velocity fluctuations in Minas
Passage, the tidal power community will have - for the first time - a reliable basis for assessing the effects of
turbulence on turbine design, performance and operational life in this and similarly challenging environments.