scholarly journals Frontal and tilted PDV probes for measuring velocity history of laser-shock induced calibrated particles

2014 ◽  
Vol 500 (14) ◽  
pp. 142022 ◽  
Author(s):  
G Prudhomme ◽  
P Mercier ◽  
L Berthe ◽  
J Bénier ◽  
P-A Frugier
Keyword(s):  
Laser Shock ◽  
History Of ◽  
Velocity History

scholarly journals Unsteady Effects During Resistance Tests on a Ship Model in a Towing Tank

2008 ◽  
Vol 52 (04) ◽  
pp. 263-273
Author(s):  
Lawrence J. Doctors ◽  
Alexander H. Day ◽  
David Clelland
Keyword(s):  
Wave Resistance ◽  
Excellent Correlation ◽  
Experiment Data ◽  
Towing Tank ◽  
Ship Model ◽  
History Of ◽  
Rate Of Decay ◽  
Unsteady Effects ◽  
Velocity History ◽  
Resistance Tests

It is known that there are oscillations in the wave resistance during the constant-velocity phase of a towing-tank resistance test on a ship model. In this work, the unsteady thin-ship resistance theory has been applied to this case. The results have been compared with experiment data obtained using a towing carriage the velocity history of which can be programmed. It is demonstrated here that generally excellent correlation exists between the theory and the experiments. In particular, one can predict the influence of Froude number, rate of acceleration, and type of smoothing of the acceleration on the characteristics of the oscillations. These characteristics include the amplitude, rate of decay, frequency, and phasing of the oscillations in the curve of wave resistance versus time.

Experimental and Numerical Investigation into Dynamic Spall Damage of Porous Phenolic Composites

2010 ◽  
Vol 160-162 ◽  
pp. 106-112
Author(s):  
Zhi Gang Zhu ◽  
Zhi Liang Wang ◽  
Yong Chi Li
Keyword(s):  
Damage Evolution ◽  
Strain Wave ◽  
Wave Problem ◽  
Evolution Law ◽  
One Dimensional ◽  
Spall Damage ◽  
History Of ◽  
Velocity History ◽  
Phenomenological Point ◽  
Good Agreement

A damage evolution law for porous phenolic composites is developed by using phenomenological point, which along with the improved Johnson-Cook model is then implemented into a finite difference code for one-dimensional strain wave problem. The velocity history of free-face particle is recorded and correlated with the simulated result to evaluate the damage parameters. Good agreement shows that the proposed damage evolution law and spall rule are feasible. Besides, the relationships between the striking velocity of flyer and the spall thickness as well as spall time are investigated. This study provides a methodology to quantify the damage evolution of phenolic composites under impact loading.

scholarly journals Meander migration: the observation method

2017 ◽  
Vol 54 (8) ◽  
pp. 1104-1117
Author(s):  
Jean-Louis Briaud ◽  
Axel M. Montalvo-Bartolomei
Keyword(s):  
Full Scale ◽  
Case Histories ◽  
Site Specific ◽  
The Past ◽  
History Of ◽  
Lateral Extent ◽  
Observation Method ◽  
Velocity History ◽  
Over Time ◽  
Meander Migration

River meanders migrate over time and the consequences of this migration can create a problem for bridges and embankments near the river. This is why it is important to predict the lateral extent of future migration over the life of neighboring infrastructure. In the observation method for meander migration (OMM), the past movement and velocity history of the meander are used to back-calculate site specific erosion parameters. Those parameters serve as input to predict the meander migration for a chosen future velocity hydrograph. In this article and after a review of existing knowledge, the analytical steps leading to the development of the OMM are described, then the field and laboratory work at four full-scale meander migration case histories are presented, and then the four full-scale meander migration case histories are used to evaluate the OMM. The OMM has been automated in an Excel spreadsheet.

Accurate measurement of the velocity history of a laser-driven foil plate with a push–pull-type VISAR

2001 ◽  
Vol 40 (34) ◽  
pp. 6327 ◽  
Author(s):  
Hongliang He ◽  
Takamichi Kobayashi ◽  
Toshimori Sekine
Keyword(s):  
History Of ◽  
Velocity History

Numerical Simulation of the Interaction Between Two Bubbles Rising in the Water

2010 ◽  
Author(s):  
Ren-qing Zhu ◽  
Yan-cheng Li ◽  
Yong-yan Ni ◽  
Pei-tao Zhang
Keyword(s):  
Bubble Diameter ◽  
Separation Distance ◽  
Bubble Deformation ◽  
Vof Model ◽  
Merging Process ◽  
History Of ◽  
Fluent Software ◽  
Movement And Deformation ◽  
Two Bubbles ◽  
Velocity History

Based on the VOF model, the rising movement and deformation of two bubbles placed horizontally or vertically with separation distance under the action of the buoyancy are simulated by using FLUENT software. The effects of distance between two bubbles on deformation, coalescence, rising velocity and path are considered. The bubble deformation is monitored and the change of velocity with time is analyzed. The influence of bubble diameter on rising and merging are discussed and the velocity history of bubble is obtained in rising and merging process. The results show that: The distance has great effect on the interaction between two bubbles in rising and merging process, the smaller the bubble spacing is, the stronger the interaction between bubbles is, and the larger the bubble diameter is, the larger the affected area is. The two bubbles placed vertically attract each other in rising process. The upper bubble has accelerative effect on the speed of lower bubble. The two bubbles placed horizontally in water attract and exclude each other periodically.

Experiments on Pulse Propagation in an Obliquely Laminated Composite

1974 ◽  
Vol 41 (4) ◽  
pp. 1052-1056 ◽  
Author(s):  
C. Sve ◽  
S. Okubo
Keyword(s):  
Pulse Propagation ◽  
Rear Surface ◽  
Laminated Composite ◽  
Theoretical Work ◽  
Surface Velocity ◽  
Capacitive Transducer ◽  
Linear Elastic ◽  
Viscosity Effects ◽  
History Of ◽  
Velocity History

Experimental results are presented for the linear elastic dynamic response of periodically laminated composites. A shock tube-capacitive transducer technique is used to determine the rear surface velocity history of three laminated samples that have different lamination angles and are subjected to a step pressure loading. Viscosity effects are discussed, and comparisons are made with predictions based on previous theoretical work.

Experimental Investigation into Spall of Carbon Phenolic Composites

2014 ◽  
Vol 887-888 ◽  
pp. 62-69
Author(s):  
Zhi Gang Zhu ◽  
Yong Chi Li
Keyword(s):  
Free Surface ◽  
Spall Strength ◽  
State Equation ◽  
Physical Characteristics ◽  
Hugoniot Curve ◽  
Gas Gun ◽  
Tensile Wave ◽  
History Of ◽  
Surface Particle ◽  
Velocity History

The velocity history of free-surface particle for carbon phenolic composites (density is 1.4g/cm3) is obtained based on the loading technology of the light gas gun, the relationship between the striking velocity of flyer and the spall thickness as well as time is investigated. Besides, spall strength and thickness are obtained by analyzing the samples data and curves. The high pressure physical characteristics, such as type Hugoniot curve and Murnagham state equation for this material, are acquired by analyzing the velocity history of free-surface and spall characteristics. This study provides a methodology to quantify spall and physical characteristics for carbon phenolic composites under tensile wave loading.

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