A large pressure pulse decay method to simultaneously measure permeability and compressibility of tight rocks

Previous data from this laboratory have revealed a large pressure pulse in small veins on the epicardial surface of the right ventricle of the rabbit. The phasic relationship between venule pressures and venule diameters in a beating heart was examined. Luminal pressures were measured in 39 different veins on the epicardial surface of the rabbit right ventricle. The venous luminal pressures averaged 12.6 mmHg maximum and 1.0 mmHg minimum. Pressures in 23 different small veins were also obtained at different right ventricular afterloads. Peak venous pressures increased with peak right ventricular pressure. The phasic diameter changes of 119 different vessels were examined. Vessel diameters decreased as luminal pressures increased. The average change in vessel diameter through a cardiac cycle was 20%, with a range from 0 to 60%. The large pulse pressures found in small veins appear to be related to decreasing vessel diameters and probably result from the displacement of blood as the vessels narrow.

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Numerical Computation of Shock Waves in a Spherical Cloud of Cavitation Bubbles

Journal of Fluids Engineering ◽

10.1115/1.2823549 ◽

1999 ◽

Vol 121 (4) ◽

pp. 872-880 ◽

Cited By ~ 64

Author(s):

Yi-Chun Wang ◽

Christopher E. Brennen

Keyword(s):

Pressure Pulse ◽

Ambient Pressure ◽

Transient Behavior ◽

Damage Potential ◽

Cloud Cavitation ◽

Cavitation Bubbles ◽

Large Pressure ◽

Spherical Cloud ◽

Bubble Interaction ◽

Physical Phenomena

The nonlinear dynamics of a spherical cloud of cavitation bubbles have been simulated numerically in order to learn more about the physical phenomena occurring in cloud cavitation. A finite cloud of nuclei is subject to a decrease in the ambient pressure which causes the cloud to cavitate. A subsequent pressure recovery then causes the cloud to collapse. This is typical of the transient behavior exhibited by a bubble cloud as it passes a body or the blade of a ship propeller. The simulations employ the fully nonlinear continuum bubbly mixture equations coupled with the Rayleigh-Plesset equation for the dynamics of bubbles. A Lagrangian integral method is developed to solve this set of equations. It was found that, with strong bubble interaction effects, the collapse of the cloud is accompanied by the formation of an inward propagating bubbly shock wave. A large pressure pulse is produced when this shock passes the bubbles and causes them to collapse. The focusing of the shock at the center of the cloud produces a very large pressure pulse which radiates a substantial impulse to the far field and provides an explanation for the severe noise and damage potential in cloud cavitation.

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Comparison of Recovery and Recrystallization in Stainless Steel Following Plane-Wave Shock Loading and Explosive Forming

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069132 ◽

1970 ◽

Vol 28 ◽

pp. 428-429 ◽

Cited By ~ 2

Author(s):

J. A. Korbonski ◽

L. E. Murr

Keyword(s):

Stainless Steel ◽

Shock Loading ◽

Pressure Pulse ◽

Shock Pressure ◽

304 Stainless Steel ◽

Strain Rates ◽

Two Dimensional ◽

Aisi 304 Stainless Steel ◽

Aisi 304 ◽

Explosive Forming

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.

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