Schlieren measurement of turbulent structure in a diffusion flame

Davis, M. R.; Rerkshanandana, P.

doi:10.1016/0894-1777(93)90017-d

Cited by 14 publications

(3 citation statements)

References 29 publications

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“…On the other hand, optical methods are mainly fast, non-intrusive and accurate [8]. There exists many optical methods such as Interferometry [9][10][11], Laser speckle technique [12], Schlieren photography [13][14][15] and Moiré deflectometry [16][17][18][19] that have been studied to obtain and visualize the temperature field of gaseous flames. All the interferometry methods, including Mach-Zehnder interferometry [20,21], Talbot interferometry [22][23][24][25] and Holographic interferometry [26,27] are based on changes in the refractive index of the gaseous products of the flame.…”

Section: Introductionmentioning

confidence: 99%

Temperature field measurement of an array of laminar premixed slot flame Jets using Mach-Zehnder interferometry

Ashrafi

Ashjaee

2015

Optics and Lasers in Engineering

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Section: Introductionmentioning

confidence: 99%

Temperature field measurement of an array of laminar premixed slot flame Jets using Mach-Zehnder interferometry

Ashrafi

Ashjaee

2015

Optics and Lasers in Engineering

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“…The schlieren system, invented by Robert Hooke in the 17th century, was developed as a visualization technique in the 19th century by Toepler [1]. Since then, the technique has been applied widely to tackle different kinds of problems in many research areas, such as combustion [2,3], aerodynamics [4,5], fluid mechanics [6,7], etc. Recently, a background oriented schlieren technique [8,9] and a novel 'synthetic schlieren' technique [10] have been developed both for qualitative visualization and quantitative measurements.…”

Section: Introductionmentioning

confidence: 99%

High speed stereoscopic shadowgraph imaging and its digital 3D reconstruction

Wang¹,

ZHANG²

2011

Meas. Sci. Technol.

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A stereoscopic shadowgraph system has been developed based on the conventional z-type schlieren configuration. The test volume is set at the intersection of two inclined converging beams formed by two pairs of parabolic mirrors. Two synchronized high speed cameras are applied to record the shadowgraph image pairs simultaneously. A precisely etched metal mesh plate is used to calibrate the stereoscopic shadowgraph system. By combining the calibration parameters and coordinates of the matching points in stereo images, the depth information and the 3D view of the shadowgraph images are obtained. A crystal block with internal 3D images created by laser etching is used as a model for static object reconstruction and validation. The 3D coordinates obtained by the digital 3D reconstruction are in good agreement with the real dimensions. The developed stereoscopic technique is then applied to investigate the bursting dynamics of a bubble. The time resolved bubble-bursting process has been reconstructed successfully. The quantitative velocity measurement reveals that the bubble collapses at a constant velocity of around 7 m s−1, which corresponds to a high Weber number. As a result, finger-like structures are observable around the rim of the collapsing bubble. The stereoscopic shadowgraph technique has been shown to be effective for 3D visualization and quantitative measurement.

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“…Various investigators [10,11] used a similar laser schlieren approach to measure the covariance of angular deflections, which was related to the local flow properties. Davis and Rerkshanandana [12][13][14] extended their previous studies to obtain convection velocity and power spectra in turbulent diffusion flames and delineated the influence of turbulent eddies on thermal mixing.…”

mentioning

confidence: 96%

Investigation of the Cross-beam Correlation Algorithm to Reconstruct Local Field Statistics from Line-of-sight Measurements in Turbulent Flows

Kolhe

Agrawal

2010

Flow Turbulence Combust

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Optical techniques such as speckle photography and rainbow schlieren deflectometry yield path integrated measurements of deflection angle instead of the local field variable such as density, temperature and/or species concentration. Thus, a reconstruction algorithm is employed to obtain the local properties from the path-integrated measurements. Cross-beam correlation (CBC) algorithm provides the link between path-integrated and local field statistics in time-averaged axisymmetric turbulent flows. Path-integrated statistics are obtained using orthogonal light rays crossing within the turbulent flow. The algorithm assumes local isotropy and negligible correlation between points on orthogonal beams, which is valid strictly in fully turbulent flows. In this study, noise-free synthetic scalar turbulence data are generated and used to determine how different assumptions in the CBC algorithm affect the reconstruction accuracy. Results show that the reconstruction accuracy is excellent for a narrow correlation function (or small integral length scale), while significant errors are incurred in case of a wide correlation function. A procedure to improve the reconstruction accuracy of the CBC algorithm is proposed in this study.

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Schlieren measurement of turbulent structure in a diffusion flame

Cited by 14 publications

References 29 publications

Temperature field measurement of an array of laminar premixed slot flame Jets using Mach-Zehnder interferometry

Temperature field measurement of an array of laminar premixed slot flame Jets using Mach-Zehnder interferometry

High speed stereoscopic shadowgraph imaging and its digital 3D reconstruction

Investigation of the Cross-beam Correlation Algorithm to Reconstruct Local Field Statistics from Line-of-sight Measurements in Turbulent Flows

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