Field-Observation of Flood in a River by Video Image Analysis

Aya, Shirou; Fujita, Ichiro; Yagyu, Mitsuhiko

doi:10.2208/prohe.39.447

Cited by 20 publications

(7 citation statements)

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“…The PIV analysis software used in this study was developed over many years by I. Fujita (Gifu University, Japan) and modified for large‐scale applications at IIHR‐Hydroscience and Engineering. The code is solid and very well‐tested in several prior field and laboratory applications [ Ettema et al , 1997; Fujita et al , 1998; Aya et al , 1995]. In the next sections, the theory behind velocity estimation using video imagery is discussed.…”

Section: Image Velocimetrymentioning

confidence: 99%

Flow measurement in streams using video imagery

Bradley

Kruger

Meselhe

et al. 2002

Water Resources Research

104

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[1] A video imagery technique for making flow measurements in streams and waterways is presented and used to estimate discharge for Clear Creek near Oxford, Iowa. A video camera was used to visualize the flow seeded with tracers. Measurements of free surface flow velocities were then made using particle image velocimetry (PIV) techniques. The velocity measurements were used as input to a hydraulic model, which uses kinematic principles (conservation of mass) to derive three-dimensional flow fields for discharge estimation. A survey of five channel cross sections over a 7.15 m length of stream were made to define the channel bathymetry for the hydraulic model. The average channel width was 5.7 m, and the average depth was 0.2 m. The discharge estimate using the video technique (0.183 m 3 /s) compares well with the current meter discharge measurement (0.192 m 3 /s with an estimated standard error of 6.4%). The root-mean square difference of the depth-averaged velocity at the locations of the current meter measurements was 0.032 m/s. Potential applications of the video imagery technique include measurements of flood flows at ungaged sites, river monitoring from a remote site, and estimation of two-and threedimensional flow components.

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Section: Image Velocimetrymentioning

confidence: 99%

Flow measurement in streams using video imagery

Bradley

Kruger

Meselhe

et al. 2002

Water Resources Research

104

View full text Add to dashboard Cite

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“…Being capable of distinguishing between these two contributions, by exploiting unseeded LSPIV, a wide current speed range measurement is allowed, from high flow regimes where large-scale turbulence structures convected by the main flow prevail, to the lowest ones, where unseeded LSPIV recognizes mostly capillary-gravity waves traveling with their own celerity on the free-surface. This paper focuses on the latter, because the former has already been validated by many authors ( [1], [2], [9], [12], [13], [14], [15], [20], [26]). Besides this, a novel procedure to orthorectify images is proposed and some case studies are described.…”

Section: Introductionmentioning

confidence: 99%

Unseeded large scale PIV measurements corrected for the capillary-gravity wave dynamics

Benetazzo

Gamba

Barbariol

2017

Rend. Fis. Acc. Lincei

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Large Scale Particle Image Velocimetry (LSPIV) is widely recognized as a reliable method to measure water surface velocity field in open channels and rivers. LSPIV technique is based on a camera view that frames the water surface in a sequence, and image-processing methods to compute water surface displacements between consecutive frames. Using LSPIV, high flow velocities, as for example flood conditions, were accurately measured, whereas determinations of low flow velocities is more challenging, especially in absence of floating seeding transported by the flow velocity. In fact, in unseeded conditions, typical surface features dynamics must be taken into account: besides surface structures convected by the current, capillary-gravity waves travel in all directions, with their own dynamics.Discrimination between all these phenomena is here discussed, providing a new method to distinguish and to correct unseeded LSPIV measurements associated with wavy structures, accounting for their phase speed magnitude and direction. This has been done measuring wavenumber vectors by using the same images exploited for PIV analysis. All measurements are performed without any flow seeding and in total absence of suspended materials, using the specular reflection of the water surface as a key marker. Results obtained at low-flow regimes in a straight concrete-made rectangular-section channel and in a river are satisfying, especially if compared to those obtained from classic LSPIV application without discrimination and correction. Moreover, a novel simple and safe procedure to orthorectify images is here presented.

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“…The first image velocimetry measurements in rivers were made in Japan in the mid‐1990s [ Fujita and Komura , 1994; Aya et al , 1995; Fujita et al , 1997]. The technique has subsequently undergone continuous development and testing in anticipation of hydraulic applications [ Muste et al , 2004a].…”

Section: Introductionmentioning

confidence: 99%

Large‐scale particle image velocimetry for measurements in riverine environments

Muste

Fujita

Hauet

2008

Water Resources Research

335

285

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[1] Large-scale particle image velocimetry (LSPIV) is a nonintrusive approach to measure velocities at the free surface of a water body. The raw LSPIV results are instantaneous water surface velocity fields, spanning flow areas up to hundreds of square meters. Measurements conducted in typical conditions in conjunction with appropriate selections of parameters for image processing resulted in mean velocity errors of less than 3.5%. The current article reviews the background of LSPIV and the work of three research teams spanning over a decade. Implementation examples using various LSPIV configurations are then described to illustrate the capability of the technique to characterize spatially distributed two-and three-dimensional flow kinematic features that can be related to important morphologic and hydrodynamic aspects of natural rivers. Finally, results and a critique of research methods are discussed to encourage LSPIV use and to improve its capabilities to collect field data needed to better understand complex geomorphic, hydrologic, and ecologic river processes and interactions under normal and extreme conditions. Citation: Muste, M., I. Fujita, and A. Hauet (2008), Large-scale particle image velocimetry for measurements in riverine environments, Water Resour. Res., 44, W00D19,

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Field-Observation of Flood in a River by Video Image Analysis

Cited by 20 publications

References 0 publications

Flow measurement in streams using video imagery

Flow measurement in streams using video imagery

Unseeded large scale PIV measurements corrected for the capillary-gravity wave dynamics

Large‐scale particle image velocimetry for measurements in riverine environments

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