A compact light sheet generator for flow visualizations

Diemunsch, G.; Prenel, Jean-Pierre

doi:10.1016/0030-3992(87)90052-1

Cited by 28 publications

(12 citation statements)

References 4 publications

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“…An ideal laser module has to be able to produce a light sheet that has a consistent thickness so that the recorded field of view's dimensions are constant throughout the whole flow field. This generates high signal to noise ratio and low amount of parasite scattered light [7] [8]. Doing this enables a trustworthy qualitative and quantitative observation of spatial flow structures [5].…”

Section: Methodsmentioning

confidence: 98%

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Flow Visualization and Modeling for Education and Research in Sedimentary Processes: An Accessible and Inexpensive Alternative

Motanated¹

2017

GEP

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Sedimentary processes have direct effects on the geometry, distribution, and geophysical and geochemical properties of sedimentary rocks. Being able to qualitatively and quantitatively visualize the movement vector of sediments in fluid media is essential for understanding the complicated earth surface processes. Nonintrusive measuring and observing the interaction between the movement of fluid media and particles by a laser sheet flow visualization technique requires a light source that is thin and monochromatic. Yet, an ideal laser sheet generator is rather expensive and inaccessible, especially for schools and universities residing in low-income countries. This project is proposing a less-expensive option for a laser sheet source for nonintrusive flow visualization and modeling. Here, cylindrical lens is used to convert from point laser into sheet laser. Multiple combinations of laser diodes of various wavelength (nanometer) and power (milliwatt) and cylindrical lenses of various dimensions are analyzed. The pair that is able to produce the thinnest and brightest light sheet is not only effective but also affordable. The combination of manufactured laser module of 532 nm 50 mW and a single rod lens is able to generate a light sheet that is less than 4 mm thick. When choosing a laser module, this research recommends one at a wavelength of 532 nm with any electric power (high wattage results in high lumens).

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Section: Methodsmentioning

confidence: 98%

“…Typical manufactured laser modules generate laser dot; thus, beam shaping optics are required to convert laser dot into laser sheet [5] [6] [8]. Cylindrical optical components have been used to produce static laser sheets/planes and are regularly used in both aerodynamics and hydrodynamics experiments [7].…”

Section: Methodsmentioning

confidence: 99%

Flow Visualization and Modeling for Education and Research in Sedimentary Processes: An Accessible and Inexpensive Alternative

Motanated¹

2017

GEP

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“…Efficient illumination of the target along a line segment is provided by a combination of spherical and cylindrical lenses similar to that used in well-established methods for laser light sheet generation. 9 This approach enables independent tailoring of the width and length of the line segment on target. The lens combination includes one spherical component and an associated cylindrical lens that are positioned to transform the collimated laser beam into a line of minimal width (~100 µm).…”

Section: Initial Tests and Experimental Methodsmentioning

confidence: 99%

Shock-induced explosive chemistry in a deterministic sample configuration.

Stuecker¹,

Castañeda²,

Cesarano³

et al. 2005

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Explosive initiation and energy release have been studied in two sample geometries designed to minimize stochastic behavior in shock-loading experiments. These sample concepts include a design with explosive material occupying the hole locations of a close-packed bed of inert spheres and a design that utilizes infiltration of a liquid explosive into a well-defined inert matrix. Wave profiles transmitted by these samples in gas-gun impact experiments have been characterized by both velocity interferometry diagnostics and three-dimensional numerical simulations. Highly organized wave structures associated with the characteristic length scales of the deterministic samples have been observed. Initiation and reaction growth in an inert matrix filled with sensitized nitromethane (a homogeneous explosive material) result in wave profiles similar to those observed with heterogeneous explosives. Comparison of experimental and numerical results indicates that energetic material studies in deterministic sample geometries can provide an important new tool for validation of models of energy release in numerical simulations of explosive initiation and performance.3

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“…In this configuration, established techniques of laser light sheet generation [14] can be used to tailor independently the width and length of the illumination line segment on target. With this approach, the target illumination optics are completely decoupled from the collection optics in general and the focal length of L1, in particular.…”

Section: A Line-imaging Orvis Methodsmentioning

confidence: 99%

“…The length of the line segment, on the other hand, is determined by the positions and focal lengths of the second and third cylindrical lenses in combination with the spherical lens. [14] With the position of the spherical lens fixed to provide the minimal line width, the second and third cylindrical lenses are moved (essentially in tandem) to vary the line length as desired. Very thin (<150 µm) line segments can be produced in this manner, as illustrated in Fig.…”

Section: A Line-imaging Orvis Methodsmentioning

confidence: 99%

Dispersive Velocity Measurements in Heterogeneous Materials

Trott¹,

Castañeda²,

O'Hare³

et al. 2000

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In order to provide real-time data for validation of three dimensional numerical simulations of heterogeneous materials subjected to impact loading, an optically recording velocity interferometer system (ORVIS) has been adapted to a line-imaging instrument capable of generating precise mesoscopic scale measurements of spatially resolved velocity variations during dynamic deformation. Combining independently variable target magnification and interferometer fringe spacing, this instrument can probe a velocity field along line segments up to 15 mm in length. In high magnification operation, spatial resolution better than 10 µm can be achieved. For events appropriate to short recording times, streak camera recording can provide temporal resolution better than 0.2 ns. A robust method for extracting spatially resolved velocity-time profiles from streak camera image data has been developed and incorporated into a computer program that utilizes a standard VISAR analysis platform. The use of line-imaging ORVIS to obtain measurements of the mesoscopic scale dynamic response of shocked samples has been demonstrated on several different classes of heterogeneous materials. Studies have focused on pressed, granular sugar as a simulant material for the widely used explosive HMX. For low-density (65 percent theoretical maximum density) pressings of sugar, material response has been investigated as a function of both impact velocity and changes in particle size distribution. The experimental results provide a consistent picture of the dispersive nature of the wave transmitted through these samples and reveal both transverse and longitudinal wave structures on mesoscopic scales. This observed behavior is consistent with the highly structured mesoscopic response predicted by 3-D simulations. Preliminary line-imaging ORVIS measurements on HMX as well as other heterogeneous materials such as foam and glassreinforced polyester are also discussed.4

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A compact light sheet generator for flow visualizations

Cited by 28 publications

References 4 publications

Flow Visualization and Modeling for Education and Research in Sedimentary Processes: An Accessible and Inexpensive Alternative

Flow Visualization and Modeling for Education and Research in Sedimentary Processes: An Accessible and Inexpensive Alternative

Shock-induced explosive chemistry in a deterministic sample configuration.

Dispersive Velocity Measurements in Heterogeneous Materials

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