In Situ Turbulence Replication Evaluation And Measurement

The flow through tidal passages is, by nature, extremely turbulent and this flow speed variability affects the reliability and efficiency of energy extraction and the operational risks for in-stream turbines. The accurate measurement and numerical modelling of turbulence for these conditions is, therefore, important for designing and deploying any tidal technology and assessing the risk and cost of operation.

InSTREAM is co-funded by the Offshore Energy Research Association, a Nova Scotia based not-for-profit research group, and InnovateUK, a government-funded business and innovation organization. The Government of Canada (NRC-IRAP) has provided additional funding to the Canadian partners while in Europe,
the project was recently given the prestigious EUREKA label designation.

The objectives of the InSTREAM project are to develop a set of sensors and methods that can be used at tidal energy sites as well as laboratory-scale simulators, and measure turbulence over a wide range of temporal and spatial scales to capture time-averaged turbulence quantities as well as turbulent intermittency. The
latter is important for understanding occurrence rates of extreme loading events.

InSTREAM will feature a sensor system that combines standard flow measurement technology (i.e., acoustic and electro-magnetic) with novel non-acoustic measurement technology (i.e., shear probes) to create a system that is useful for turbulence bservations in both laboratory and field applications. The system will be
deployed at three sites: at the (1) FloWaveTT Energy Research Facility in Edinburgh to test and validate the laboratory configuration; (2) EMEC’s Fall-of-Warness site as a first field location; (3) at the FORCE Minas Passage site as the second field location.

In terms of instrumentation, the InSTREAM addresses shortcomings of existing measurement technology to reliably and consistently resolve high-wave number turbulent velocity scales, in laboratory and tidal channel settings. The InSTREAM deployment methodology allows “real-world” field measurements to be down-translated to tank-scale measurements and vice-versa, providing developers and manufacturers the ability to evaluate dynamic behaviour of sites and turbine designs at model scale and full scale.

The results from this applied research project address technical challenges that ultimately reduce uncertainties in site design, yield assessments, and device design, leading to improved cost structure and access to financing by reducing economic risk