DETERMINATION SOUND SPEED OF METAL IN AQUEOUS SOLUTION VIA LASER INDUCED ACOUSTIC WAVE TECHNIQUE

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Maisarah Duralim ◽  
Noriah Bidin ◽  
Waskito Nugroho ◽  
Jasman Zainal
Keyword(s):  
Shock Wave ◽  
Aqueous Solution ◽  
Acoustic Wave ◽  
Sound Speed ◽  
High Speed ◽  
Optical Breakdown ◽  
High Speed Photography ◽  
Nonlinear Phenomena ◽  
Metal Element ◽  
Laser Induced Breakdown

Laser induced breakdown and shock wave propagation are nonlinear phenomena. The high temperature and high pressure associated with plasma formation offering a lot advantages in industrial and scientific research.  However not many realized that the end  product of nonlinear effect such as the generation of acoustic wave will also attribute to significant impact. Thus the intention of this study is to materialize the usefulness of such acoustic wave for determination the sound speed of metal element like Pb, Hg and K in aqueous solution. In this attempt a Q-switched Nd:YAG laser was focused to induce optical breakdown and its associated shock wave generation which later  follow by the generation of acoustic wave. The phenomenon is observed in conjunction with high speed photography based shadowgraph technique. The experimental results of sound speed for K, Hg and Pb is found in good agreement with the standard value from references. This confirmed that laser induced acoustic wave will be other alternative method for measuring sound speed for metal element in periodic table.

A study of the collapse of arrays of cavities

1988 ◽  
Vol 190 ◽  
pp. 409-425 ◽  
Author(s):  
J. P. Dear ◽  
J. E. Field
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
High Speed Photography ◽  
Cavitation Damage ◽  
Major Mechanism ◽  
Collapse Mechanisms ◽  
Multiple Jets ◽  
Circular Holes ◽  
Schlieren Photography ◽  
Thick Glass

This paper describes a method for examining the collapse of arrays of cavities using high-speed photography and the results show a variety of different collapse mechanisms. A two-dimensional impact geometry is used to enable processes occurring inside the cavities such as jet motion, as well as the movement of the liquid around the cavities, to be observed. The cavity arrangements are produced by first casting water/gelatine sheets and then forming circular holes, or other desired shapes, in the gelatine layer. The gelatine layer is placed between two thick glass blocks and the array of cavities is then collapsed by a shock wave, visualized using schlieren photography and produced from an impacting projectile. A major advantage of the technique is that cavity size, shape, spacing and number can be accurately controlled. Furthermore, the shape of the shock wave and also its orientation relative to the cavities can be varied. The results are compared with proposed interaction mechanisms for the collapse of pairs of cavities, rows of cavities and clusters of cavities. Shocks of kbar (0.1 GPa) strength produced jets of c. 400 m s−1 velocity in millimetre-sized cavities. In closely-spaced cavities multiple jets were observed. With cavity clusters, the collapse proceeded step by step with pressure waves from one collapsed row then collapsing the next row of cavities. With some geometries this leads to pressure amplification. Jet production by the shock collapse of cavities is suggested as a major mechanism for cavitation damage.

On the Propagation of Sound in a High-Speed Non-Isothermal Shear Flow

2009 ◽  
Vol 8 (3) ◽  
pp. 199-230 ◽  
Author(s):  
L.M.B.C. Campos ◽  
M.H. Kobayashi
Keyword(s):  
Wave Equation ◽  
Shear Flow ◽  
Acoustic Wave ◽  
Sound Speed ◽  
High Speed ◽  
Shear Flows ◽  
Critical Layer ◽  
Acoustic Wave Equation ◽  
Mean Flow ◽  
Flow Vorticity

The propagation of sound in shear flows is relevant to the acoustics of wall and duct boundary layers, and to jet shear layers. The acoustic wave equation in a shear flow has been solved exactly only for a plane unidirectional homentropic mean shear flow, in the case of three velocity profiles: linear, exponential and hyperbolic tangent. The assumption of homentropic mean flow restricts application to isothermal shear flows. In the present paper the wave equation in an plane unidirectional shear flow with a linear velocity profile is solved in an isentropic non-homentropic case, which allows for the presence of transverse temperature gradients associated with the ***non-uniform sound speed. The sound speed profile is specified by the condition of constant enthalpy, i.e. homenergetic shear flow. In this case the acoustic wave equation has three singularities at finite distance (besides the point at infinity), viz. the critical layer where the Doppler shifted frequency vanishes, and the critical flow points where the sound speed vanishes. By matching pairs of solutions around the singular and regular points, the amplitude and phase of the acoustic pressure in calculated and plotted for several combinations of wavelength and wave frequency, mean flow vorticity and sound speed, demonstrating, among others, some cases of sound suppression at the critical layer.

scholarly journals STUDY OF STEEL BARRIER SURFACE AFTER HIGH-SPEED EXPOSURE OF W AND TIC POWDERS

2021 ◽  
pp. 23-27
Author(s):  
E. V. Petrov ◽  
V. S. Trofimov ◽  
V. O. Kopytskiy
Keyword(s):  
Mechanical Properties ◽  
Shock Wave ◽  
High Speed ◽  
Physical And Mechanical Properties ◽  
High Speed Photography ◽  
Shock Wave Loading ◽  
Wave Loading ◽  
Barrier Material ◽  
Barrier Surface ◽  
Powder Particles

The surface layer of an obstacle made of U8 steel is investigated after high-speed exposure to a flow of powder particles. After analyzing the frames of high-speed photography, the average velocities of movement of particles of tungsten and titanium carbide powders were determined. It is shown that the shock-wave loading of the barrier material and the effect of particles accelerated by the explosion energy provide a change in the physical and mechanical properties of the surface and the volume of the steel barrier material.

Investigation of a converging underwater shock wave using high-speed photography

1995 ◽  
Author(s):  
Shigeru Itoh ◽  
S. Kubota ◽  
Shirou Nagano ◽  
I. Morita ◽  
A. Chiba ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
High Speed Photography ◽  
Underwater Shock Wave ◽  
Underwater Shock

scholarly journals Bubbles with shock waves and ultrasound: a review

2015 ◽  
Vol 5 (5) ◽  
pp. 20150019 ◽  
Author(s):  
Siew-Wan Ohl ◽  
Evert Klaseboer ◽  
Boo Cheong Khoo
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Biomedical Applications ◽  
High Speed ◽  
Experimental Studies ◽  
High Intensity Focused Ultrasound ◽  
High Speed Photography ◽  
Sound Waves ◽  
Bubble Cloud ◽  
Bubble Interaction

The study of the interaction of bubbles with shock waves and ultrasound is sometimes termed ‘acoustic cavitation'. It is of importance in many biomedical applications where sound waves are applied. The use of shock waves and ultrasound in medical treatments is appealing because of their non-invasiveness. In this review, we present a variety of acoustics–bubble interactions, with a focus on shock wave–bubble interaction and bubble cloud phenomena. The dynamics of a single spherically oscillating bubble is rather well understood. However, when there is a nearby surface, the bubble often collapses non-spherically with a high-speed jet. The direction of the jet depends on the ‘resistance' of the boundary: the bubble jets towards a rigid boundary, splits up near an elastic boundary, and jets away from a free surface. The presence of a shock wave complicates the bubble dynamics further. We shall discuss both experimental studies using high-speed photography and numerical simulations involving shock wave–bubble interaction. In biomedical applications, instead of a single bubble, often clouds of bubbles appear (consisting of many individual bubbles). The dynamics of such a bubble cloud is even more complex. We shall show some of the phenomena observed in a high-intensity focused ultrasound (HIFU) field. The nonlinear nature of the sound field and the complex inter-bubble interaction in a cloud present challenges to a comprehensive understanding of the physics of the bubble cloud in HIFU. We conclude the article with some comments on the challenges ahead.

SHADOWGRAPHY OF SHOCK WAVE INDUCED BY DOUBLE PULSE TECHNIQUE

2015 ◽  
Vol 74 (8) ◽  
Author(s):  
Waskito Nugroho ◽  
N. E. Khamsan ◽  
M. Abdullah ◽  
K. Ganesan
Keyword(s):  
Shock Wave ◽  
Nd:Yag Laser ◽  
High Speed ◽  
Laser System ◽  
Optical Breakdown ◽  
Video Camera ◽  
Double Pulse ◽  
Pulse Technique ◽  
Camera Synchronization ◽  
Wave Induced

High-speed videography based on double pulse of Nd:YAG laser to capture dynamic expansion of shock wave is reported. A Q-switched Nd:YAG laser was employed  as an input signal and disturbance source. Nitrodye laser was utilized as a flash. The shock wave generation was recorded via CCD video camera. Synchronization is organized associated with a digital delay generator. Nd:YAG laser was focused to generate an optical breakdown in distilled water. Double pulses were generated within the interval of one second. The first pulse of Nd:YAG laser was used to trigger the dye laser and the second pulse to generate shock wave. Manipulation of delay times allow to freeze the dynamic expansion of shock wave. The double pulse technique is appropriated for laser system with the absence of external trigger unit. Lack of electronic failure is the advantage offer by the double pulse technique.

Shadowgraph of Pulse CO2 Laser Induced Breakdown in Different Pressure Air

2014 ◽  
Vol 887-888 ◽  
pp. 1001-1004 ◽  
Author(s):  
Yu Zhang ◽  
Duan Yong Li ◽  
Tao Wu
Keyword(s):  
Shock Wave ◽  
Delay Time ◽  
High Speed ◽  
Laser Energy ◽  
Early Stage ◽  
Propagation Speed ◽  
Air Pressure ◽  
Incident Laser ◽  
Incident Laser Energy ◽  
Laser Induced Breakdown

The expansion property of an infrared CO2 laser produced air plasma is characterized using a high-speed imaging shadowgraph technique. The shadowgraphs were taken by a time-gated intensified charge-coupled device at various delay times after single pulses induced gas breakdown. We examined five incident laser energy of 180, 240, 345, 420 and 600 mJ induced air breakdown at the pressure of atmospheric and 104 Pa. A shock wave produced by laser induced breakdown was also observed and its speed was measured as a function delay time between the breakdown and the shadow imaging under different air pressure. The experimental results indicated that the radial and axial shock wave front evolutions showed similar behavior, which increased fast with delay time at early stage and slowly at later stage. The propagation speed of the wavefront was about 2 cm/μs at the initial stage of breakdown, and then decreased very quickly. The propagation speed under low air pressure was higher than that of gases under high pressure and the spark sustained less time at lower pressure. The size of laser induced air spark increased with incident laser energy but not simple linear relationships.

High Speed Photography For Studying The Shock Wave Propagation At High Mach Numbers Through A Reflection Nozzle

1979 ◽  
Author(s):  
S. G. Zaytsev ◽  
E. V. Lazareva ◽  
A. V. Mikhailova ◽  
V. L. Nikolaev-Kozlov ◽  
E. I. Chebotareva
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
High Speed ◽  
Shock Wave Propagation ◽  
High Speed Photography ◽  
Mach Numbers ◽  
High Mach
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