LSPIV implementation for environmental flow in various laboratory and field cases

Abstract

Large-Scale Particle Image Velocimetry (LSPIV) is an extension of a quantitative imaging technique to measure water surface velocities using simple and inexpensive equipment. This paper describes the implementation of imaged-based LSPIV in eight different environmental flow and hydraulic engineering applications for the investigation of complex configurations with and without sediment transport (bed and suspended loads). These applications include the investigation of sedimentation in shallow reservoirs, run-of-river hydropower plants, side weirs used to control bank overflow, flow fields in different spillway configurations with and without Piano Key Weir (PKW), oil spills with flexible and rigid barriers, groin fields, river confluence, and sediment flushing in reservoirs. The paper summarises some special problems encountered in such study cases. The selection and adjustments of the parameters to solve them properly were examined. The potential of LSPIV to measure surface flow velocities in the context of river and dam engineering projects is shown. Despite significant variations of natural and artificial illuminations and seeding tracers in the laboratory, field, wind, and water surface elevation, LSPIV was applied successfully to obtain velocity measurements. LSPIV has proven to be a reliable, flexible, and inexpensive flow diagnostic tool that can be employed successfully in many engineering applications. Ó

A novel permanent gauge-cam station for surface-flow observations on the Tiber River

“…Continuous flow observations are often required in the investigation of erosion dynamics, sediment transport, and drainage network evolution (Hrachowitz et al, 2013;Montanari et al, 2013). In engineering practice, flood warning systems largely rely on real-time discharge measurements, and flow velocity monitoring is important for the design and management of hydraulic structures, such as reservoirs and hydropower plants (Kantoush et al, 2011).…”

An acoustic travel time method for continuous velocity monitoring in shallow tidal streams

“…Doppler method lacks penetration capabilities of tomography equipment [e.g., Le Coz et al, 2008], because it has greater susceptibility to interference from boundary conditions and is subject to signal attenuation from same particles needed in backscattering the signal. On the other hand, conventional optical techniques such as Large-Scale Particle Image Velocimetry are not able to measure components along the vertical axis, z [e.g., Fujita and Kunita, 2011;Kantoush et al, 2011]. These components might not only be missed, but also introduce interference in the data for the horizontal components caused by parallax particularly in nonunidirectional flows such as estuaries with complex vertical distribution of current velocity.…”

Bulk velocity measurements by video analysis of dye tracer in a macro-rough channel

“…tracking light particles transported by the flow. PIV uses a laser to illuminate particle transport by a thin layer in the flow (Raffel et al 1998, Pokrajac et al 2007, while LSPIV uses only light particles transported on the water surface (Fujita et al 1998, van Prooijen and Uijttewaal 2002, Jodeau et al 2008, Muste et al 2008, Kantoush et al 2011, Mattioli et al 2012. The light particles on the surface are representative of the surface flow velocity and recirculation cells with signatures at the free surface (van Prooijen and Uijttewaal 2002) and can be applied in shallow water, where the horizontal velocity is predominant and greatly exceeds the vertical velocity.…”