Tidal channels are highly dynamic regions of the coastal ocean that exhibit strong turbulent behaviour. High resolution measurements of vertical turbulence and mean horizontal current speeds in these regions are required by the in-stream tidal turbine industry for site characterisation. Such data can be used by industry to improve estimates of tidal dissipation rates, energy generation potential and predictions of stress on critical hardware components. The in-situ oceanographic instruments that are used to make measurements of turbulence, such as shear-probes or Doppler velocimeters can be difficult to position in the presence of large horizontal current speeds (up to 3 m/s) that are characteristic of these active tidal channels. Sea floor mounted acoustic Doppler Current Profilers (ADCP) can remotely collect turbulence data for extended periods of time and provide an alternative to in-situ instruments. However, the accuracy and limitations of these ADCP turbulence measurements in the presence of high current speeds needs to be quantified. These limitations are explored using a model of acoustic backscatter integrated with output from a Large Eddy Simulation (LES) of an idealised tidal channel measuring 1 km × 200 m × 30 m. We simulate the direct acoustic measurement of the turbulent vertical velocities.

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