Low-cost 3D mapping of turbulent flow surfaces

This work presents a new measurement technique with potential to remotely measure turbulence processes based on their linkages with the dynamic water surface. Previous work has demonstrated these linkages, but accurate 3D measurement of turbulence-generated rough water surfaces is problematic. Microsoft Kinect sensors have previously been used for measuring gravity waves in coloured (opaque) water. Here the sensor is applied to clear water surfaces, and data is validated against a conductance-based wave probe. These data show that the Kinect sensor can characterise relatively large gravity waves in clear water via the principle of refraction. The same principle is able to capture the dominant components of turbulence-generated water surfaces, though discrete features can be ambiguous. It is postulated that a flat bed would result in an unambiguous measurement. Application of this technique to turbulent flows could lead to new applications in flood studies, river monitoring, and sewer flow measurement.