The Measurement of Turbulence with the Laser-Doppler Anemometer

Buchhave, Preben; George, William K.; Lumley, John L.

doi:10.1146/annurev.fl.11.010179.002303

Cited by 283 publications

(127 citation statements)

References 13 publications

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“…The surface must be reflective to provide an adequate specular return signal to complete the measurement leg of the interferometer; this is distinctly different than the requirement of laser transmission in the laser Doppler anemometry. 34 Laser Doppler vibrometers work by interfering the reference laser light with the measurement laser light using the arrangement depicted in Fig. 2.…”

Section: Methodsmentioning

confidence: 99%

Using laser Doppler vibrometry to measure capillary surface waves on fluid-fluid interfaces

Friend

Yeo

2010

Biomicrofluidics

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Capillary wave phenomena are challenging to study, especially for microfluidics where the wavelengths are short, the frequencies are high, and the frequency distribution is rarely confined to a narrow range, let alone a single frequency. Those that have been studying Faraday capillary waves generated by vertical oscillation have chosen to work at larger scales and at low frequencies as a solution to this problem, trading simplicity in measurement for issues with gravity, boundary conditions, and the fidelity of the subharmonic capillary wave motion. Laser Doppler vibrometry using a Mach-Zehnder interferometer is an attractive alternative: The interface's motion can be characterized at frequencies up to 40 MHz and displacements of as little as a few tens of picometers.

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Section: Methodsmentioning

confidence: 99%

Using laser Doppler vibrometry to measure capillary surface waves on fluid-fluid interfaces

Friend

Yeo

2010

Biomicrofluidics

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“…The velocity measurements were phase-locked with a once-per-flow-cycle pulse sent to the BSA from the PC controlling the piston motion and each flow cycle was divided into equi-sized phase intervals for averaging. Phase-averaged velocities and r.m.s turbulent fluctuations over the duration of the 75 flow cycles were obtained by incorporating the residence time weighting to remove velocity bias, as described by Bucchave, George & Lumley (1979). For the present experiments bin sizes of 2…”

Section: Lda Measurementsmentioning

confidence: 99%

Experimental study of the turbulent boundary layer in acceleration-skewed oscillatory flow

O’Donoghue

Davies

et al. 2011

J. Fluid Mech.

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Experiments have been conducted in a large oscillatory flow tunnel to investigate the effects of acceleration skewness on oscillatory boundary layer flow over fixed beds. As well as enabling experimental investigation of the effects of acceleration skewness, the new experiments add substantially to the relatively few existing detailed experimental datasets for oscillatory boundary layer flow conditions that correspond to full-scale sea wave conditions. Two types of bed roughness and a range of highReynolds-number, Re ∼ O(10 6 ), oscillatory flow conditions, varying from sinusoidal to highly acceleration-skewed, are considered. Results show the structure of the intrawave velocity profile, the time-averaged residual flow and boundary layer thickness for varying degrees of acceleration skewness, β. Turbulence intensity measurements from particle image velocimetry (PIV) and laser Doppler anemometry (LDA) show very good agreement. Turbulence intensity and Reynolds stress increase as the flow accelerates after flow reversal, are maximum at around maximum free-stream velocity and decay as the flow decelerates. The intra-wave turbulence depends strongly on β but period-averaged turbulent quantities are largely independent of β. There is generally good agreement between bed shear stress estimates obtained using the loglaw and using the momentum integral equation, and flow acceleration skewness leads to high bed shear stress asymmetry between flow half-cycles. Turbulent Reynolds stress is much less than the shear stress obtained from the momentum integral; analysis of the stress contributors shows that significant phase-averaged vertical velocities exist near the bed throughout the flow cycle, which lead to an additional shear stress, −ρũw; near the bed this stress is at least as large as the turbulent Reynolds stress.

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“…LIF has been utilized in RIM systems by Diez et al (2005), Ovdat and Berkowitz (2006), Liu et al (2006a, b), Ravelet et al (2007), Wu et al (2011), , , amongst others. (ii) Laser Doppler velocimetry (LDV), laser/phase Doppler anemometry (LDA/PDA), and similar approaches have been detailed by Durst et al (1976Durst et al ( , 1997, Buchhave et al (1979), Tropea (1995), Albrecht et al (2003) and Czarske (2006). These methods allow the measurement of local velocity and/or droplet size within an interrogated volume and have been used in RIM systems by Varty (1984), Yarlagadda and Yoganathan (1989), Walker et al (1989), Liu et al (1989), Duncan et al (1990), Chen and Kadambi (1990), Wildman et al (1992), Koh et al (1994), Jana (1995), Perktold et al (1997), Dietze et al (2009), and others.…”

Section: Introductionmentioning

confidence: 99%

A review of solid–fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid–liquid and multiphase solid–liquid flows

2017

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Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid–liquid and solid–liquid–liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid–liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330–1.620 and 1.251–1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid–liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity

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The Measurement of Turbulence with the Laser-Doppler Anemometer

Cited by 283 publications

References 13 publications

Using laser Doppler vibrometry to measure capillary surface waves on fluid-fluid interfaces

Using laser Doppler vibrometry to measure capillary surface waves on fluid-fluid interfaces

Experimental study of the turbulent boundary layer in acceleration-skewed oscillatory flow

A review of solid–fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid–liquid and multiphase solid–liquid flows

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