Large-scale particle image velocimetry for flow analysis in hydraulic engineering applications

Large-Scale Particle Image Velocimetry (LSPIV), as presented herein, is an extension of particle image velocimetry (PIV), which aims at providing velocity fields spanning large flow areas in laboratory or field conditions. Additional data, such as mappings of large-scale flow structures and discharges are readily obtainable using LSPIV. While the image- and data-processing algorithms are similar to conventional PIV, adjustments are required for illumination, seeding procedures, and pre-processing of the recorded images. This paper describes the implementation of video-based LSPIV in three hydraulic engineering applications covering surfaces from 4 m(2) to 45,000 m(2). These applications are: gas-transfer processes downstream a model spillway, ice conveyance through a model river confluence, and flood plain flow in a full-scale river. The special problems encountered in each of these experiments, as well as the selection and adjustments of the parameters to properly solve them, are examined. LSPIV has proven to be a reliable, flexible, and economically efficient flow diagnostic tool that can be employed successfully in the surveillance planning, design, hazard warning, operation, and management in water-related activities.