Application of a Digital Particle Image Velocimetry (DPIV) System to Breaking Waves in the Surf Zone

Craig, Kenneth R.; Thieke, Robert J.

doi:10.1061/9780784402429.048

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…Using the newer method of particle image velocimetry (PIV) the full velocity field can be obtained. PIV can still not be used in aerated regions, but, applied with care, the method can be successful in capturing velocities in some other difficult situations such as in the crest of a broken wave (see for example Craig & Thieke 1996). present an experimental study using PIV to investigate turbulence in a spilling breaker.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of wave run-up at a steep beach

2003

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This paper presents experiments on run-up of strongly nonlinear waves on a beach of 10.54° inclination. Velocity fields are obtained by the PIV (particle image velocimetry) technique. Acceleration measurements are also attempted, but it is difficult to obtain useful results in every case. In addition, free-surface profiles are extracted from digital images and wave resistance probes. The investigation focuses on the dynamics of the early stages of the run-up, when steep fronts evolve in the vicinity of the equilibrium shoreline, but maximum run-up heights are also reported. Measurements on moderately nonlinear waves are compared to results from long-wave theories, including a numerical Boussinesq model and analytic shallow-water results from the literature. In particular the applicability of the long-wave theories is addressed. However, most attention is given to run-up of high incident solitary waves that are on the brink of breaking at the shoreline. In one case a temporarily slightly overturning wave front is found that neither develops into a plunger or displays appreciable spilling. This feature is discussed in view of measured velocity and acceleration patterns and with reference to the dam-break problem. Effects of scaling, as well as viscous damping, are also briefly discussed.

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Section: Introductionmentioning

confidence: 99%

An experimental study of wave run-up at a steep beach

2003

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“…These measurements have more recently been complemented by the application of digital video particle image velocimetry (DPIV) techniques to measuring surf zone flow fields [ Craig and Thieke , 1996; Chang and Liu , 1996; Govender et al , 1996, 2002]. In an effort to obtain measurements in the highly aerated wave crest and roller region, Craig and Thieke [1996] attempted to extract the aerated field through image filtering, while Govender [1999], Govender et al [2002], and Alport et al [1998, 1999] have made use of the bubble structure in the application of digital correlation image velocimetry (DCIV) techniques.…”

Section: Introductionmentioning

confidence: 99%

Video‐imaged surf zone wave and roller structures and flow fields

2002

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[1] The measurement of mean water levels, roller geometries, and phase ensembleaveraged velocity and turbulence intensity fields under spilling and plunging waves breaking in a two-dimensional laboratory surf zone is presented. The velocities were measured using digital correlation image velocimetry, while water levels and roller geometries were determined through gray scale filtering of video images. The phase ensemble-averaged horizontal and vertical components of velocity and turbulence intensities are measured throughout the entire flow domain, including the wave roller area, by utilizing the aerated areas as part of the flow structure. The time-averaged horizontal velocities (undertow), turbulence intensities, and turbulent kinetic energies are determined by averaging across the wave phase. Turbulence magnitudes are found to compare favorably with existing laser Doppler anemometry measurements below the wave trough level, where such measurements have generally been confined because of aeration contamination effects. The significantly higher velocity and turbulence intensity magnitudes measured above the trough level in the present experiments highlight the novel nature of the present investigation for describing flow regimes in the surf zone. INDEX

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“…Recent work of Earnshaw and Greated (1998) has investigated the dynamics of vortices formed by and shed from artificial ripples under oscillatory motion utilizing PIV technique to acquiring detailed velocity measurements at several phases of oscillation for four flow conditions. Graig II and Thieke (1996) used the mathematical definition of crosscorrelation introduced by Willert and Gharib (1991) to measure the velocity in the aerated crest of a broken wave within the transition region. Gallagher and Symour (1992) measured the time-varying sediment transport in the first half cycle using video imaging of dyed natural sand.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Bottom Boundary Layer Dynamics of Movable Bed by using Enhanced PIV Technique

Ahmed

Sato

2001

Coastal Engineering Journal

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The behavior of the bottom boundary layer of a natural rippled bed and plane bed is investigated utilizing PIV technique. An enhanced approach of the PIV is developed on the basis of the Minimum Quadratic Difference (MQD), which is better compared with the conventional cross-correlation method. Information of pixels below the instantaneous unmoved level is expelled from the calculation process so that the velocity close to the bed is computed accurately. The flow field over the natural rippled bed is measured with the enhanced approach and comparison with the LDV measurements showed that the measurements of flow field by the enhanced PIV are in a good agreement with the LDV measurements.Having verified the technique, the technique is utilized to measure the net volume flux of sand transported in sheetflow under asymmetric oscillation. The net mass transport is measured to be compared with the PIV measurement. The sand concentration is estimated from brightness through a calibration relationship. The velocity is measured and then the volume flux is integrated. It was found that the technique predicted net onshore transport although it slightly underestimated the volume flux.

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Application of a Digital Particle Image Velocimetry (DPIV) System to Breaking Waves in the Surf Zone

Cited by 3 publications

References 4 publications

An experimental study of wave run-up at a steep beach

An experimental study of wave run-up at a steep beach

Video‐imaged surf zone wave and roller structures and flow fields

Investigation of Bottom Boundary Layer Dynamics of Movable Bed by using Enhanced PIV Technique

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