The turbulent/non-turbulent interface at the outer boundary of a self-similar turbulent jet

Westerweel, J.; Hofmann, Thomas; Fukushima, Chiharu; Hunt, J. C. R.

doi:10.1007/s00348-002-0489-5

Cited by 87 publications

(94 citation statements)

References 10 publications

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“…The slope of the curve changes at a value of around 0.03. This value (0.03), interestingly matches with that of Westerweel et al (2002), and has therefore been chosen as the threshold value in Eqs. 1 and 2.…”

Section: Determination Of Threshold Valuementioning

confidence: 95%

“…The two regions can be readily identified by adding dye to one region and using laser or some other light source for illumination (Dimotakis et al 1983;Westerweel et al 2002). Prasad and Sreenivasan (1989) used thresholding to determine the scalar interface of an axisymmetric turbulent jet.…”

Section: Introductionmentioning

confidence: 99%

“…Note that such a criterion can be used with DNS data because of the availability of all three components of vorticity, which is usually not the case with experimental data. Westerweel et al (2002Westerweel et al ( , 2005 and Holzner et al (2006) employed a novel method of performing PIV and flow visualization (LIF) concurrently on an axisymmetric turbulent-free jet and oscillating grid, respectively, to overcome this difficulty. While a threshold in concentration provided by the LIF data was used for interface detection, the PIV data were used to obtain conditionally averaged quantities across the interface.…”

Section: Introductionmentioning

confidence: 99%

“…While a threshold in concentration provided by the LIF data was used for interface detection, the PIV data were used to obtain conditionally averaged quantities across the interface. However, the approach of Westerweel et al (2002) is somewhat cumbersome in that two synchronized cameras viewing the same area and preferably positioned on opposite sides of the test section have to be employed. The noise content in the measurements and the finite resolution of PIV further complicates matters.…”

Section: Introductionmentioning

confidence: 99%

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Detection of turbulent/non-turbulent interface for an axisymmetric turbulent jet: evaluation of known criteria and proposal of a new criterion

2009

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In this paper, we evaluate several criteria for the detection of turbulent/non-turbulent interface using direct numerical simulation and particle image velocimetry data of an axisymmetric turbulent jet. The possibility of identifying the interface from information available in wholefield velocity data alone is also explored. The present results using a Concentration thresholding technique compare well against available results obtained using a similar detection criterion. It is noted that Concentration and Vorticity criteria are difficult to apply with standard PIV data and therefore a new criterion based on azimuthal vorticity and streamwise velocity-quantities available from such data, is proposed. The proposed criterion scores over previously employed criteria in terms of its simplicity of evaluation, and can possibly be applied to other flows not tested here. The instantaneous location of the interface as detected from the different criteria differs substantially. However, the conditionally averaged streamwise velocity, azimuthal vorticity, and Reynolds shear stress across the interface obtained from the new criterion, as well as from the previous criteria, agree reasonably well against available results. The present work further suggests that different criteria, even with slightly sub-optimal threshold value, can provide quantitatively similar ensemble-averaged results.

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Section: Determination Of Threshold Valuementioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Detection of turbulent/non-turbulent interface for an axisymmetric turbulent jet: evaluation of known criteria and proposal of a new criterion

2009

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“…The two-point correlations in the streamwise direction in an axisymmetric jet at a Reynolds number of 2000 were also computed from PIV measurements performed by Fukushima et al (2000) and discussed in Westerweel et al (2002). This database was used here to compute the streamwise two-point correlations of two velocity components (streamwise and radial) both on and off the jet centreline.…”

Section: Experimental Methodology and Uncertaintymentioning

confidence: 99%

Two-point similarity in the round jet

Ewing

Frohnapfel

George³

et al. 2007

J. Fluid Mech.

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The governing equations for the two-point velocity correlations in the far field of the axisymmetric jet are examined and it is shown that these equations can have equilibrium similarity solutions for jets with finite Reynolds number that retain a dependence on the growth rate of the jet. The two-point velocity correlation can be written as the product of a scale that depends on the downstream position of the two points and a function that only depends on the similarity variables. Physically, this result implies that the turbulent processes producing and dissipating energy at the different scales of motion, as well as transferring energy between the different scales of motion, are in equilibrium as the flow evolves downstream. A particularly interesting prediction from the analysis is that the two-point similarity solutions depend only on the separation distance between the points in the streamwise similarity coordinate (i.e. υ = ξ − ξ ), that is, the logarithm of the streamwise coordinate itself (i.e. ξ = ln x 1 , where x 1 is measured from a virtual origin). Thus, the measures of the turbulence are homogeneous in the streamwise similarity coordinate.The predictions from the similarity analysis for the streamwise two-point velocity correlation were compared with combined hot-wire and LDA measurements on the centreline of a round jet at a Reynolds number of 33 000, and with two-point velocity correlations computed from PIV measurements in a round jet at a Reynolds number of 2000 performed by Fukushima et al. In both cases, the measured twopoint velocity correlations in the streamwise direction collapsed when they were scaled in the manner predicted by the similarity analysis. The results provide further evidence that the equilibrium similarity hypothesis does describe the development of the flow in fully developed turbulent round jets and that the two-point correlations are statistically homogeneous in the streamwise similarity coordinate.

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Dynamic Open Contours Using Particle Swarm Optimization with Application to Fluid Interface Extraction

Thomas

Misra

Kambhamettu

et al. 2006

Computer Vision – ACCV 2006

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The turbulent/non-turbulent interface at the outer boundary of a self-similar turbulent jet

Cited by 87 publications

References 10 publications

Detection of turbulent/non-turbulent interface for an axisymmetric turbulent jet: evaluation of known criteria and proposal of a new criterion

Detection of turbulent/non-turbulent interface for an axisymmetric turbulent jet: evaluation of known criteria and proposal of a new criterion

Two-point similarity in the round jet

Dynamic Open Contours Using Particle Swarm Optimization with Application to Fluid Interface Extraction

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