Author(s): Richard I. Wilson; Heide Friedrich; Craig Stevens
Keywords: Buoyancy; obstacle; sediment-laden flow; turbidity; visualization
Abstract: A novel photometric thresholding process for the study of opaque, sediment-laden flows is presented. The method has been developed to allow photometry and visually intrusive, conventional flow measurement instruments to be used simultaneously. Sediment-laden gravity currents of varying densities were released in a lock-exchange flume containing intrusive ultrasonic Doppler velocity profiling (UVP) probes, siphon tubes and a basal obstacle. A new approach to flume illumination and development of a binary noise-reducing algorithm suited to turbidity currents are presented. Additionally, a standard deviation filtering procedure is introduced. The combined process improves the visibility of opaque currents and optimizes current front recognition around visual obstructions. This offers a key advancement to previous photometric techniques and provides a practical way forward for laboratory experiments on sediment-laden flows.