Density measurements using the Background Oriented Schlieren technique

Venkatakrishnan, L.; Meier, G. E. A.

doi:10.1007/s00348-004-0807-1

Cited by 262 publications

(142 citation statements)

References 17 publications

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“…However, schlieren and shadowgraph techniques can be difficult, time consuming and costly, as they require large mirrors or lenses and precise alignment. Conversely, BOS captures the density field but only requires a CCD camera, light source, and a background, making it a much simpler and less costly option for flow visualization 1 . BOS is based on background distortion or an apparent movement of the background when imaged through a density field onto a detector plane 2 .…”

Section: A Background Oriented Schlierenmentioning

confidence: 99%

Background Oriented Schlieren Applied to Study Shock Spacing in a Screeching Circular Jet

Clem

Zaman

Fagan

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Section: A Background Oriented Schlierenmentioning

confidence: 99%

Background Oriented Schlieren Applied to Study Shock Spacing in a Screeching Circular Jet

Clem

Zaman

Fagan

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…Diagnostics of flows in supersonic and hypersonic facilities by BOS has been carried out in references [22][23][24][25][26], while in references [27][28][29] BOS has been used in the outdoors, with a large field of view. Several improvements of the technique are proposed, mainly in obtaining 3D measurements by tomographic imaging, [30][31][32], or by increasing the accuracy through colored backgrounds, [33].…”

Section: Principles Of Bosmentioning

confidence: 99%

Review of background oriented schlieren and development for ballistic range applications

Gojani

Kamishi

Obayashi

2013

EPJ Web of Conferences

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Abstract. Quantitative measurements of fluid flow can be achieved by flow visualization techniques, and this paper reviews and outlines background oriented schlieren, with emphasis on its performance: measurement sensitivity and uncertainty. Since the technique depends on cross-correlation, an assessment of image evaluation is also conducted. Background oriented schlieren is applied to two flows: shock reflection from a wedge in a shock tube, and natural cooling by convection. It is estimated that the technique can be applied to ballistic facilities.

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“…The background-oriented technique relies on visualizing shifts in focused images with a set background. Differences between subsequent images can be recorded and analyzed using numerical computing software, as done by Venkatakrishnan and Meier (Venkatakrishnan and Meier, 2004). The background oriented Schlieren technique will be considered for a future study of the geometry discussed in this paper.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of Natural Convection in a Rectangle Using Schlieren Imaging

Doherty¹,

Dillon²,

Roberts³

2017

Frontiers in Heat and Mass Transfer

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The onset of turbulence in natural convection systems is difficult to predict using traditional computational techniques. The flow patterns that occur before and after the onset of turbulence may be better understood with the help of visual techniques like Schlieren imaging. Schlieren imaging allows visualization of the density gradients of a fluid using collimated light and refractive properties. In this experiment, a device was designed to test the behavior of airflow with non-isothermal boundary conditions within a rectangular cavity. Previous computational fluid modeling suggested a period doubling route to chaos in a cavity with a high aspect ratio and free convection flow driven by two non-isothermal walls. To visualize this system, two strip heaters were attached to two 56 cm long plates. The plates were set to an aspect ratio of 10 and sealed with gaskets and garolite. With a Z-type Schlieren device, the existence of two definitive cells was confirmed, and the oscillation point between the two cells was found above the cavity midpoint. At steady state, a thin-wire thermocouple was placed at the inflection point to measure fluctuations in temperature. Consistent oscillations in temperature were observed that indicated a steady interacting boundary layer, while non-periodic oscillations indicated the initial transition to turbulence. It was observed that there was a transition from a mostly steady interacting boundary layer at set-point 35 o C to near-turbulence at 65 o C. At higher Rayleigh numbers the transition behavior predicted in the computational fluid model was confirmed, although the size of the convection cells was not uniform.

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Density measurements using the Background Oriented Schlieren technique

Cited by 262 publications

References 17 publications

Background Oriented Schlieren Applied to Study Shock Spacing in a Screeching Circular Jet

Background Oriented Schlieren Applied to Study Shock Spacing in a Screeching Circular Jet

Review of background oriented schlieren and development for ballistic range applications

Experimental Validation of Natural Convection in a Rectangle Using Schlieren Imaging

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