Airside velocity measurements over the wind-sheared water surface using particle image velocimetry

Shaikh, Nasiruddin; Siddiqui, Kamran

doi:10.1007/s10236-008-0132-y

Cited by 10 publications

(23 citation statements)

References 28 publications

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“…• Wave-following Eulerian averaging: in order to obtain time-averaged quantities especially for high amplitudes waves, Hsu and Hsu [13] as Shaikh and Siddiqui [1] use another system they show as more accurate and meaningful. They transformed the fixed Eulerian coordinate system into a wave-following Eulerian system.…”

Section: Piv Qualitative Analysismentioning

confidence: 99%

“…As PIV measurements provide instantaneous velocity fields, they contain both mean and turbulent component of the velocity. As summarised by Shaikh and Siddiqui [1], the instantaneous velocity over a wavy surface is the sum of mean, turbulent and wave induced velocities. The conventional fluctuating velocity component u' and v' are computed using the Reynolds decomposition: U (t) = Um + u' (t)…”

Section: Momentum Interaction Between Water and Air Phasesmentioning

confidence: 99%

“…Shaikh and Siddiqui [1], Friebel [19] make the observation that the positive Reynolds stress in the air phase just above an interface indicates that the transport of the turbulence is done towards the water surface. Using the same analogy, Shaikh and Siddiqui [1] observes that negative Reynolds stress in the air at the interface corresponds to the momentum flux transported from the fluctuating liquid surface to the gas phase. A similar discussion holds for water PIV analysis.…”

Section: Momentum Interaction Between Water and Air Phasesmentioning

confidence: 99%

“…This lack of knowledge comes mainly from the difficulties to measure with accuracy physical quantities in the near interface region. In carrying a study of wind-wave flumes in oceanography, Shaikh and Siddiqui [1] show that PIV is a reliable optical nonintrusive measurement technique for investigating interface problem.…”

Section: Introductionmentioning

confidence: 99%

“…Another limitation in the previous near interface PIV studies is the lack of simultaneous measurements. Indeed, lots of measurements and analysis are done either in the liquid phase [3,4] or in the gas phase [1], but very none are addressed to simultaneous measurements in both phases.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Experimental investigation of a 2d impinging jet on a liquid surface

Berger¹,

Depardon²,

Rambaud³

et al. 2009

Computational Methods in Multiphase Flow V

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An experimental investigation of impinging 2d planar air jet on a water surface is performed by means of Particle Image Velocimetry (PIV). The difficulty encountered to measure the two dimensional velocity and turbulence fields close to the interface requires a special treatment of the PIV data obtained in the air and water sides. The resulting technique enables the localisation of the moving interface, the use of the inter-correlation and the calculation of statistics in both phases. The results show that the proposed PIV interface detection technique is in good agreement with the LeDaR detection technique developed at the von Karman Institute. The analysis of the air and water velocity field close to the interface highlights the topological differences between dimpling and incipient splashing configurations. The results obtained in this study will serve to model later turbulence transfer in impinging jet configuration.

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Section: Piv Qualitative Analysismentioning

confidence: 99%

Section: Momentum Interaction Between Water and Air Phasesmentioning

confidence: 99%

Section: Momentum Interaction Between Water and Air Phasesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Experimental investigation of a 2d impinging jet on a liquid surface

Berger¹,

Depardon²,

Rambaud³

et al. 2009

Computational Methods in Multiphase Flow V

View full text Add to dashboard Cite

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Near-surface flow structure over wind-generated water waves, part I: wave-induced flow characteristics

Shaikh

Siddiqui

2010

Ocean Dynamics

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We report on an experimental study conducted to investigate the influence of small-scale wind waves on the airflow structure in the immediate vicinity of the air-water interface. PIV technique was used to measure the twodimensional velocity fields at wind speeds of 3.7 and 4.4 m s −1 and at a fetch of 2.1 m. The flow structure was analyzed as a function of wave phase. In the near-surface region, significant variations were observed in the flow structure over the waveform. The phase-averaged profiles of velocity, vorticity, and Reynolds stress showed different behavior on the windward and leeward sides of the wave in the near-surface region. The influence of waveinduced velocity was restricted within a distance of three significant wave heights from the surface, which also showed opposite trends on the windward and leeward sides of the crest. The results also show that the turbulent Reynolds stress mainly supports downward momentum transfer whereas the wave-induced Reynolds stress is responsible for the upward momentum transfer from wave to wind. In the immediate vicinity of the air-water interface, the momentum is transferred from waves to wind along the windward side, whereas, the momentum transfer is from wind to waves along the leeward side.

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Near-surface flow structure over wind-generated water waves, part II: characteristics of separated and non-separated flows

Shaikh

Siddiqui

2010

Ocean Dynamics

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This article is the continuation of the previous work reported in the companion paper (part I). The same experimental data were further investigated to compare the airside flow behavior over separated and non-separated flow fields over wind-generated water waves. Particle image velocimetry technique was used to measure the two-dimensional velocity fields at wind speeds of 3.7 and 4.4 ms −1 and at a fetch of 2.1 m. An algorithm was developed to segregate separated and non-separated velocity fields within the measured dataset. The results show that the waves over which the flow separation occurs are steeper and larger in amplitude than the waves with no flow separation. The results also show that the influence of flow separation is mainly restricted on the crest-to-trough region. Within the separation region, lower magnitudes of the streamwise velocity and higher magnitudes of the vorticity were observed for the separated flow than that for the nonseparated flow fields. The turbulence is significantly enhanced within the separation zone. It was also observed that the flow separation did not influence the turbulence behavior and magnitude on the windward side of the wave. The enhanced Reynolds stress is positive on the leeward side which indicates that the flow separation increases downward momentum transfer from wind to the wave. The profiles of the wave-induced velocity and Reynolds stress show that the flow separation influences the wave-induced characteristics over the entire waveform.

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Airside velocity measurements over the wind-sheared water surface using particle image velocimetry

Cited by 10 publications

References 28 publications

Experimental investigation of a 2d impinging jet on a liquid surface

Experimental investigation of a 2d impinging jet on a liquid surface

Near-surface flow structure over wind-generated water waves, part I: wave-induced flow characteristics

Near-surface flow structure over wind-generated water waves, part II: characteristics of separated and non-separated flows

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