Luminescent Oil-Film Skin-Friction Meter

Liu, Tianshu; Sullivan, John P.

doi:10.2514/2.538

Cited by 46 publications

(23 citation statements)

References 17 publications

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“…In this approach, the distance away from the interface is encoded by the particle's intensity according to Lambert-Beer's law. Other depth from attenuation methods also uses the imaged intensity in a similar way to assess information from interfacial regions (Liu and Sullivan 1998). The technique that is presented in this paper is an extension of current absorption-based techniques.…”

Section: Interfacial Measurement Techniquementioning

confidence: 99%

Bichromatic particle streak velocimetry bPSV

et al. 2012

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We propose a novel technique for threedimensional three-component (3D3C) interfacial flow measurement. It is based on the particle streak velocimetry principle. A relatively long integration time of the camera is used for capturing the movement of tracer particles as streaks on the sensor. The velocity along these streaks is extracted by periodically changing the illumination using a known pattern. A dye with different absorption characteristics in two distinct wavelengths is used to color the fluid. The depth of particles relative to the fluid interface can then be computed from their intensities when illuminated with light sources at those two different wavelengths. Hence, from our approach, a bichromatic, periodical illumination together with an image processing routine for precisely extracting particle streak features is used for measuring 3D3C fluid flow with a single camera. The technique is applied to measuring turbulent Rayleigh-Bénard convection at the free air-water interface. Using Lagrangian statistics, we are able to demonstrate a clear transition from the Batchelor regime to the Richardson regime, both of which were postulated for isotropic turbulence. The relative error of the velocity extraction of our new technique was found to be below 0.5 %.

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Section: Interfacial Measurement Techniquementioning

confidence: 99%

Bichromatic particle streak velocimetry bPSV

et al. 2012

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“…(The use of fluorescent pigments with ultraviolet light in producing bright images has been reported previously, including for determining skin friction. 1,2,[20][21][22][23][24] Based on previous experience, a kerosene carrier evaporates readily in such test conditions to leave a dry trace within 10 s. For the present experiments, a mixture of kerosene and fluorescent chalk with a small quantity of silicone oil was found to be suitable. The exact composition required some trial and error but, generally, the mixture should have a consistency of syrup.…”

Section: Surface Flow Visualization Requirementsmentioning

confidence: 99%

New Developments in Surface Oil Flow Visualization

Pierce

Lu²,

Bryant

et al. 2010

27th AIAA Aerodynamic Measurement Technology and Ground Testing Conference

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The prolific application of digital imaging and image processing for studying flows is extended to surface oil flow visualization. The use of colored, fluorescent mixtures enable bright, high-contrast images to be obtained which facilitate image processing. Examples were provided in visualizing the surface flow past micro vortex generators. Image processing of video sequences revealed minute features that are critical in understanding the flow.

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“…Two UV lamps were used to excite the luminescent oil. Since the luminescent intensity is proportional to the oil thickness on a wall when oil is sufficiently thin, the oil concentration or thickness measurement can be converted to luminescence measurement by using a CCD camera with a 580-nm-long-pass optical filter (Liu & Sullivan 1998).…”

Section: Luminescent Oil Visualization and Global Skin Friction Diagnmentioning

confidence: 99%

“…To measure the process of deposition of droplets with increasing time at an early stage of t = 10-45 s, luminescent oil visualizations were conducted by using the olive oil doped with a small amount of a UV dye. When the oil thickness is optically thin, the luminescent emission projected onto a camera is proportional to the concentration of deposited droplets when the droplets are not connected, or the oil film thickness when the droplets are connected to form a continuous film (Liu & Sullivan 1998. For simplicity of expression, in this paper, the term "oil film thickness" also represents "concentration of deposited droplets" when deposited droplets are discretely distributed in luminescence measurements.…”

Section: Global Patterns Of Deposited Dropletsmentioning

confidence: 99%

Deposition of micron liquid droplets on wall in impinging turbulent air jet

et al. 2009

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The fluid mechanics of deposition of micron liquid (olive oil) droplets on a glass wall in an impinging turbulent air jet is studied experimentally. The spatial patterns of droplets deposited on a wall are measured by using luminescent oil visualization technique, and the statistical data of deposited droplets are obtained through microscopic imagery. Two distinct rings of droplets deposited on a wall are found, and the mechanisms of the formation of the inner and outer rings are investigated based on global diagnostics of velocity and skin friction fields. In particular, the intriguing effects of turbulence, including large-scale coherent vortices and small-scale random turbulence, on micron droplet deposition on a wall and coalescence in the air are explored.

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Luminescent Oil-Film Skin-Friction Meter

Cited by 46 publications

References 17 publications

Bichromatic particle streak velocimetry bPSV

Bichromatic particle streak velocimetry bPSV

New Developments in Surface Oil Flow Visualization

Deposition of micron liquid droplets on wall in impinging turbulent air jet

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