High-speed imaging in fluids

Versluis, Michel

doi:10.1007/s00348-013-1458-x

Cited by 153 publications

(87 citation statements)

References 120 publications

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“…The ejection process has hardly been visualized because of the extremely short time of the process and, consequently, the process is poorly understood. The ejection time scale is estimated to be only τ ∼ V=L ∼ 100 ns, assuming a velocity V ≈ 100 m=s and a length scale L ≈ 10 μm [18], resulting in challenging visualization conditions. So far, time-resolved visualization has been achieved for relatively thick liquid-film [19][20][21][22][23] and solid-phase [24][25][26] or pastetransfer [27,28] processes.…”

Section: Introductionmentioning

confidence: 99%

Ejection Regimes in Picosecond Laser-Induced Forward Transfer of Metals

et al. 2015

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Laser-induced forward transfer (LIFT) is a 3D direct-write method suitable for precision printing of various materials, including pure metals. To understand the ejection mechanism and thereby improve deposition, here we present visualizations of ejection events at high-spatial (submicrometer) and hightemporal resolutions, for picosecond LIFT of copper and gold films with a thickness 50 nm ≤ d ≤ 400 nm. For increasing fluences, these visualizations reveals the fluence threshold below which no ejection is observed, followed by the release of a metal cap (i.e., a hemisphere-shaped droplet), the formation of an elongated jet, and the release of a metal spray. For each ejection regime, the driving mechanisms are analyzed, aided by a two-temperature model. Cap ejection is driven by relaxation of thermal stresses induced by laser-induced heating, whereas jet and spray ejections are vapor driven (as the metal film is partly vaporized). We introduce energy balances that provide the ejection velocity in qualitative agreement with our velocity measurements. The threshold fluences separating the ejection regimes are determined. In addition, the fluence threshold below which no ejection is observed is quantitatively described using a balance between the surface energy and the inertia of the (locally melted) film. In conclusion, the ejection type can now be controlled, which allows for improved deposition of pure metal droplets and sprays.

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Section: Introductionmentioning

confidence: 99%

Ejection Regimes in Picosecond Laser-Induced Forward Transfer of Metals

et al. 2015

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“…Thoroddsen et al (2008) and Versluis (2013) present overviews of the various techniques of shadowgraphy and its application in the domain of fluid dynamics. It involves taking shadow images of objects illuminated by light sources, such as high-power LEDs (Gebauer et al, 2016) or lasers with different beam geometries (Lindken and Merzkirch, 2002;Sathe et al, 2010;Tokuhiro et al, 1999), at very high frame rates.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous in situ characterisation of bubble dynamics and a spatially resolved concentration profile: a combined Mach–Zehnder holography and confocal Raman-spectroscopy sensor system

Guhathakurta

Schurr

Rinke

et al. 2017

J. Sens. Sens. Syst.

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Abstract. For a reaction between a gaseous phase and a liquid phase, the interaction between the hydrodynamic conditions, mass transport and reaction kinetics plays a crucial role with respect to the conversion and selectivity of the process. Within this work, a sensor system was developed to simultaneously characterise the bubble dynamics and the localised concentration measurement around the bubbles. The sensor system is a combination of a digital Mach-Zehnder holography subsystem to measure bubble dynamics and a confocal Raman-spectroscopy subsystem to measure localised concentration. The combined system was used to investigate the chemical absorption of CO 2 bubbles in caustic soda in microchannels. The proposed set-up is explained and characterised in detail and the experimental results are presented, illustrating the capability of the sensor system to simultaneously measure the localised concentration of the carbonate ion with a good limit of detection and the 3-D position of the bubble with respect to the spot where the concentration was measured.

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“…The development of modern day high-speed photography (Versluis 2013;Josserand & Thoroddsen 2016) added submillisecond time resolution to the measurements. FIGURE 1.…”

Section: Introductionmentioning

confidence: 99%

Wrapping up a century of splashes

Meer

2016

J. Fluid Mech.

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Few fluid phenomena are as beautiful, fragile and ephemeral as the crown splash that is created by the impact of an object on a liquid. The crown-shaped phenomenon and the physics behind it have mesmerised and intrigued scientists for over a century, and still the scientific world has not yet uncovered all of the secrets of the splash. This is exemplified in a particularly striking manner in Marston et al. (J. Fluid Mech., vol. 794, 2016, pp. 506-529) where a 6 m tall vacuum chamber is employed to study the splash formed upon impact of a sphere onto a deep liquid pool, at both atmospheric and reduced ambient pressures. They shed light into the classical problem of the surface seal and study the buckling of the splash. With an almost magical touch they devise a method to create a splash without the liquid and the sphere ever coming into contact. The images that accompany the paper -taken with state-of-the-art high-speed cameras -are as stunning as the physics that is uncovered in them.

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High-speed imaging in fluids

Cited by 153 publications

References 120 publications

Ejection Regimes in Picosecond Laser-Induced Forward Transfer of Metals

Ejection Regimes in Picosecond Laser-Induced Forward Transfer of Metals

Simultaneous in situ characterisation of bubble dynamics and a spatially resolved concentration profile: a combined Mach–Zehnder holography and confocal Raman-spectroscopy sensor system

Wrapping up a century of splashes

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