scholarly journals Investigation of Hypersonic Conic Flows Generated by Magnetoplasma Light-Gas Gun Equipped With Laval Nozzle

2021 ◽  
Author(s):  
Pavel P. Khramtsov
Keyword(s):  
Shock Wave ◽  
Experimental Study ◽  
Mach Number ◽  
Focal Plane ◽  
High Speed ◽  
Hypersonic Flows ◽  
High Speed Camera ◽  
New Approach ◽  
Gas Gun ◽  
Flow Generation

This chapter introduces new approach of hypersonic flow generation and experimental study of hypersonic flows over cones with half- angles τ1 = 3◦ and τ2 = 12◦. Mach number of the of the incident flow was M1 = 18. Visualization of the flow structure was made by the schlieren method. Straight Foucault knife was located in the focal plane of the receiving part of a shadow device. Registration of shadow patterns was carried out using high- speed camera Photron Fastcam (300 000 fps) with an exposure time of 1 μs. The Mach number on the cone was calculated from inclination angle of shock wave in the shadowgraph.

scholarly journals Диагностика полей плотности фотометрическим теневым методом при гиперзвуковом обтекании конуса в легкогазовой баллистической установке

2019 ◽  
Vol 89 (10) ◽  
pp. 1506
Author(s):  
П.П. Храмцов ◽  
В.А. Васецкий ◽  
В.М. Грищенко ◽  
М.В. Дорошко ◽  
М.Ю. Черник ◽  
...  
Keyword(s):  
Shock Wave ◽  
Hypersonic Flow ◽  
High Speed ◽  
Laval Nozzle ◽  
Frame Rate ◽  
Optical Methods ◽  
High Speed Camera ◽  
Incident Flow ◽  
Shadow Method ◽  
Flow Generation

A new method of hypersonic flow generation is proposed and the results of an experimental study of hypersonic flow past cones with half-angles = 3° and = 12° are presented. The Mach numbers of the studied incident flows were = 18 ( = 3°) and = 14.4 ( = 12°). The use of a light-gas facility, where an accelerating channel was replaced with Laval nozzle, allows us to obtain a hypersonic outflow with optical density sufficiently high for flow visualization and diagnostics with the help of optical methods. The flow structure was visualized by means of the shadow method using the Foucault knife and the slit. Shadowgraphs were recorded by a high-speed camera with a frame rate of 300,000 fps and an exposure time of 1 µs. The Mach number for the incident flow was calculated from the inclination angle of the shock wave on shadowgraphs.

The Collapse of a Gas Bubble Attached to a Solid Wall by a Shock Wave and the Induced Impact Pressure

1983 ◽  
Vol 105 (3) ◽  
pp. 341-347 ◽  
Author(s):  
Y. Tomita ◽  
A. Shima ◽  
K. Takahashi
Keyword(s):  
Shock Wave ◽  
Experimental Study ◽  
Pressure Transducer ◽  
High Speed ◽  
Solid Wall ◽  
Wall Pressure ◽  
Gas Bubble ◽  
High Speed Camera ◽  
The Impact ◽  
Collapse Process

An experimental study was made on the collapse of a gas bubble attached to a solid wall by a shock wave. The collapse process of the bubble and the induced impact wall pressure were measured simultaneously by means of a high speed camera and a pressure transducer, respectively. Consequently, it was found that the impact wall pressure was very sensitive to the factors such as the bubble size, the strength of shock wave and the distance from the origin of shock wave to the gas bubble, and in some cases it became larger than that generated by a shock wave directly impinging on the solid wall without a gas bubble.

scholarly journals Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
M. F. Uddin ◽  
H. Mahfuz ◽  
S. Zainuddin ◽  
S. Jeelani
Keyword(s):  
Energy Absorption ◽  
Polyurethane Foam ◽  
High Speed ◽  
Failure Modes ◽  
High Speed Camera ◽  
Test Results ◽  
Ballistic Performance ◽  
Gas Gun ◽  
Set Up ◽  
Control Samples

We report improving ballistic performance of polyurethane foam by reinforcing it with nanoscaleTiO2particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt% of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs) in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nanophased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nanophased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

Exfoliation of Marine Organisms Technology by Using Underwater Shock Wave

2005 ◽  
Author(s):  
Toshiaki Watanabe ◽  
Hirofumi Iyama ◽  
Ayumi Takemoto ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Marine Organisms ◽  
High Speed Camera ◽  
Sluice Gate ◽  
Underwater Shock Wave ◽  
Manual Operation ◽  
Fluid Resistance ◽  
Personnel Expenses ◽  
Underwater Shock

Adhesion problem of marine organisms often becomes a problem, in the case of ship, marine floating construction and sluice gate of power plant. These make fluid resistance of a hull increase, cause a buoyancy fall, or cause reducing coolant etc. Although these are chiefly removed by manual operation now, immense expense and immense labors, such as personnel expenses and time and effort, are needed. We tried application of an underwater shock wave, in order to solve these problems. Interference of a shock wave and the mechanism of marine organisms exfoliation were explored using the explosive and PMMA plate, which imitated a marine organisms adhesion. The process of exfoliation of organisms from PMMA plate was observed by using of the high-speed camera.

Experimental Study of Kick up Phenomenon in Thermosonic Wire-Bonding

2012 ◽  
Vol 160 ◽  
pp. 77-81
Author(s):  
Jing Jing Tian ◽  
Lei Han
Keyword(s):  
Image Processing ◽  
Experimental Study ◽  
High Speed ◽  
Gold Wire ◽  
Wire Bonding ◽  
Processing Method ◽  
Experimental Results ◽  
High Speed Camera ◽  
Depth Study ◽  
Thermosonic Wire Bonding

Kick-up phenomenon during looping is an important factor in thermosonic wire bonding. In this study, the loping process during wire bonding was recorded by using high-speed camera, and wire profiles evolution was obtained from images sequence by image processing method. With a polynomial fitting, the wire loop profiling was described by the curvature changing, and kick-up phenomenon on gold wire was found between the instant of 290th frame(0.0537s) to 380th frame (0.0703s), the change of curvature is divided into three phases, a looping phase, a mutation phase and a kick-up phase. While in the kick-up phase, the kick up phenomenon is the most obvious. These experimental results were useful for in-depth study of kick-up phenomenon by simulation.

Experimental Study on the Response Characteristics of Oilcans under High-Velocity Fragment Impact

2012 ◽  
Vol 510 ◽  
pp. 500-506
Author(s):  
Chang Hai Chen ◽  
Xi Zhu ◽  
Hai Liang Hou ◽  
Li Jun Zhang ◽  
Ting Tang
Keyword(s):  
Experimental Study ◽  
High Velocity ◽  
High Speed ◽  
Room Temperature ◽  
Experimental Results ◽  
Fuel Oil ◽  
High Speed Camera ◽  
Response Characteristics ◽  
Fuel Oils ◽  
The Impact

To explore the deflagration possibility of the warship cabin filled with fuel oil under impact of high-speed fragments in the condition of room temperature, experiments were carried out employing the small aluminium oilcans filled with fuel oil. Response processes of the oilcans were observed with the help of a high-speed camera. The disintegration as well as flying scattering of the oilcans were analyzed. The reasons for atomization of the fuel oils were presented. Finally, the deflagration possibility of warship oil cabin was analyzed. Results show that the pressure inside the oilcan is quite great under the impact of the high-speed fragment, which makes the oilcan disintegration and flying scattering. Simultaneously, fuel oils inside the oilcans are atomized quickly followed by ejected in front and back directions. Under the same condition as in present tests, deflagration will not occur for fuel oils used by warships. Experimental results will provide valuable references for the deflagration analysis of warship fuel oil cabins subjected to the impact of high-velocity fragments.

Fragmentation of acoustically levitating droplets by laser-induced cavitation bubbles

2016 ◽  
Vol 805 ◽  
pp. 551-576 ◽  
Author(s):  
Silvestre Roberto Gonzalez Avila ◽  
Claus-Dieter Ohl
Keyword(s):  
Shock Wave ◽  
Experimental Study ◽  
Surface Tension ◽  
Cavitation Bubble ◽  
High Speed ◽  
Size Range ◽  
Sound Field ◽  
Negative Pressures ◽  
Impulsive Pressure ◽  
Small Bubbles

We report on an experimental study on the dynamics and fragmentation of water droplets levitated in a sound field exposed to a single laser-induced cavitation bubble. The nucleation of the cavitation bubble leads to a shock wave travelling inside the droplet and reflected from pressure release surfaces. Experiments and simulations study the location of the high negative pressures inside the droplet which result into secondary cavitation. Later, three distinct fragmentation scenarios are observed: rapid atomization, sheet formation and coarse fragmentation. Rapid atomization occurs when the expanding bubble, still at high pressure, ruptures the liquid film separating the bubble from the surrounding air and a shock wave is launched into the surrounding air. Sheet formation occurs due to the momentum transfer of the expanding bubble; for sufficiently small bubbles, the sheet retracts because of surface tension, while larger bubbles may cause the fragmentation of the sheet. Coarse fragmentation is observed after the first collapse of the bubble, where high-speed jets emanate from the surface of the droplet. They are the result of surface instability of the droplet combined with the impulsive pressure generated during collapse. A parameter plot for droplets in the size range between 0.17 and 1.5 mm and laser energies between 0.2 and 4.0 mJ allows the separation of these three regimes.

Basic Study on the Crushing of Frozen Soil by Shock Loading

2007 ◽  
Author(s):  
Toshiaki Watanabe ◽  
Hironori Maehara ◽  
Masahiko Otsuka ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Shock Loading ◽  
Underwater Explosion ◽  
Frozen Soil ◽  
High Speed Camera ◽  
Underwater Shock Wave ◽  
Basic Study ◽  
Underwater Shock ◽  
A New Technique

The aim of study is to confirm a new technique that can crush the frozen soil and/or ice block using underwater shock wave generated by the underwater explosion of explosive. This technique can lead to the earlier sowing, which can have the larger harvest because the duration of sunshine increases. Especially, in Hokkaido prefecture, Japan, if the sowing is carried out in April, we can expect to have 150% of harvest in the ordinary season. This technique is effective against the cold regions. For example, Korea, China, Mongolia, Russia, Norway, and Sweden, etc. At first, we carried out experiments usung a detonating fuse and ice block. The process of ice breaking was observed by means of a high-speed camera. In order to check about that influence we tried to give an actual frozen soil a shock wave.

Development of a test method and experimental study on cable unwinding

2020 ◽  
pp. 095440622095449
Author(s):  
Ji-Heon Kang ◽  
Kun-Woo Kim ◽  
Jae-Wook Lee ◽  
Yong-Jae Cho ◽  
Jin-Seok Jang
Keyword(s):  
Experimental Study ◽  
Textile Industry ◽  
High Speed ◽  
Translational Motion ◽  
Control Device ◽  
Test Method ◽  
Experimental Device ◽  
High Speed Camera

In addition to the textile industry, unwinding of cable or fiber is used in various fields such as electronics, communication, and guided weapons. The cable released from the package exhibit a complicated behavior, entailing a combination of rotational and translational motion. This causes problems such as entangling and fracture. Therefore, it is necessary to study boundary and adhesion conditions to prevent unwinding failure. In this study, an experimental device for the analysis of cable unwinding was developed, and unwinding behavior was analyzed experimentally under various unwinding conditions. The experimental device comprises a jig for high-speed camera measurements, control device, and cable unwinding device. Cable behavior was analyzed according to the unwinding velocity and the distance between the fiber package and the point where the fiber was released. In addition, unwinding behavior with respect of the tension acting on the cable was analyzed experimentally by applying the adhesive.

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