STANDARD FOR APPLICATION METHOD OF LSPIV TO SURFACE VIDEO RECORD OF ACTUAL FLOOD FLOW

Using a surface video record of a large-scale flood in Yoshino River, Shikoku, Japan, some problems related to application method of Large Scale Particle Image Velocimetry (LSPIV) are examined in detail. First, from a hydraulic point of view, a new method is proposed for exclusion of incorrect velocity data and calculation of time-averaged velocity. Second, decision standards are examined with respect to the primary LSPIV model parameters. As a result, it was confirmed that the appropriate time-interval, template size and detection area size for PIV analysis procedure range between 1/3 to 1/2 seconds, between 1.5 to 2 times the maximum size of brightness pattern and about 2 times the estimated displacement distance of templates, respectively.