Vertical Microstructure Profiler: Validation of shear sensors in supercritical angle of attack and pressure sensor to measure mean velocity and stream-wise turbulence

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The Vertical Microstructure Profiler, VMP, measures microstructure turbulence in oceans, lakes and rivers by having the device sink or rise through the water column to measure velocity fluctuations at up to 200 Hz in both cross-axial directions. Our river hydrokinetic research group will investigate, in collaboration with Rockland Scientific International, extending the VMP's functionality. The VMP-250 will be tested at the University of Manitoba water tunnel. Shear probes currently measure velocity fluctuations at relative angles of attack less than 20 degrees. The angle of attack limitation of 20 degrees has never been systematically tested. For supercritical angles of attack, the response of the shear probes is unknown, a condition that occurs when the VMP is not drifting with the mean flow velocity and the flow speed is more than twice the profiler sinking or rising rate. A rubberized mount will be designed to secure the VMP-250 probe in the water tunnel with the ability to change the angle of attack using a cylinder placed upstream. A series of water tunnel tests will be conducted to investigate the accuracy of turbulence measurement for relative angle of attacks up to 60 degrees. Rockland Scientific International will fabricate a high frequency response pressure sensor to add to the VMP tested in the water tunnel. A data processing algorithm to measure velocity fluctuations in the stream-wise direction and the mean flow velocity using the pressure sensor will be developed and investigated for accuracy and reliability. This project will contribute to the field of aquatic turbulence research in science and engineering, particularly in high flow environments such as rivers and tidal channels, with applications in climate change research and marine renewable energy. The project will enable Rockland Scientific International, the world market leader in shear probes, to expand the functionality of VMP devices to better address new market demands.