Dynamics of a Submerged Ring-Stiffened Spherical Shell

1971 ◽  
Vol 38 (2) ◽  
pp. 408-417 ◽  
Author(s):  
Y. K. Lou ◽  
J. M. Klosner
Keyword(s):  
Spherical Shell ◽  
Acoustic Field ◽  
Transient Behavior ◽  
Approximate Solutions ◽  
Cylindrical Wave ◽  
Shell Structures ◽  
Acoustic Medium ◽  
Dynamic Factor ◽  
Fluid Interface ◽  
Modal Expansion

The transient response of a ring-stiffened spherical shell to a sudden pressure increase in the surrounding acoustic medium is investigated. A modal expansion approach is used to analyze the shell, while the acoustic field equation is solved by invoking the Helmholtz integral. Coupling of the two fields occurs through the enforcement of continuity of the velocity components at the shell-fluid interface. Two solutions to the same problem are obtained by using plane and cylindrical wave approximations of the acoustic field. These approximate solutions fail to predict the transient behavior for the shell configuration analyzed. The result of this study indicates that a large dynamic factor must be assumed in the design of submerged, stiffened, spherical shell structures, if explosive loads are likely to be encountered.

scholarly journals Interaction of a Ring-Reinforced Shell and a Fluid Medium

1968 ◽  
Vol 35 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Jerry W. Berglund ◽  
Jerome M. Klosner
Keyword(s):  
Circular Cylindrical Shell ◽  
Salt Water ◽  
Power Series Expansion ◽  
Cylindrical Wave ◽  
Acoustic Medium ◽  
Steel Shell ◽  
Fluid Medium ◽  
Transient Dynamic ◽  
Wave Approximation ◽  
Fluid Field

This work is concerned with the transient dynamic response of a periodically ring-reinforced, infinitely long, circular cylindrical shell to a uniform pressure suddenly applied through the surrounding acoustic medium. The incident particle velocity is zero, and the rings are assumed to be slightly flexible. A classical theory of the Donnell type is used to analyze the shell while the fluid is described by the linear acoustic field equation. The solution is obtained by assuming a power series expansion in the ring stiffness parameter and utilizing a technique which reduces the transient dynamic problem to an equivalent steady-state formulation. Numerical results are presented for a steel shell immersed in salt water for different ring spacings. For the case of rigid rings, a cylindrical and plane wave approximation was also used to represent the fluid field. It is shown that the cylindrical wave approximation yields reasonably accurate results. Flexible ring results, although limited, indicate that undamped or nonradiating components of the shell vibration are activated.

Ultra-flyweight hydrophobic poly(m-phenylenediamine) aerogel with micro-spherical shell structures as a high-performance selective adsorbent for oil contamination

RSC Advances ◽  
2014 ◽  
Vol 4 (90) ◽  
pp. 49000-49005 ◽  
Author(s):  
Xun Song ◽  
Siwei Yang ◽  
Lin He ◽  
Shuai Yan ◽  
Fang Liao
Keyword(s):  
Spherical Shell ◽  
High Performance ◽  
Shell Structures ◽  
Oil Contamination ◽  
Selective Adsorbent

Ultra-flyweight hydrophobic poly(mphenylenediamine) aerogel which can be used as high-performance selective adsorbent for oil contamination was fabricated via a simple two step approach from a poly(m-phenylenediamine) micro-spherical shell.

Simulation and Experiment Researches on Acoustic Field of Spherical Shell Focused Ultrasonic Transducer

2013 ◽  
Vol 770 ◽  
pp. 281-284
Author(s):  
Zhen Yin ◽  
Hua Li ◽  
Zi Yang Cao ◽  
Yu Can Fu
Keyword(s):  
Spherical Shell ◽  
Acoustic Field ◽  
Acoustic Pressure ◽  
Ultrasonic Transducer ◽  
Pressure Curve ◽  
Bending Vibration ◽  
Element Simulation ◽  
Ultrasonic Technology ◽  
Simulation And Experiment ◽  
Simulation Results

Aiming at the deficiency of existing focused ultrasonic technology, a new high-power Spherical Shell Focused Ultrasonic Transducer (SSFUT) was designed. The SSFUT is composed of a sandwich piezoelectric ultrasonic transducer and a bending vibration spherical shell. Simulation on acoustic field of SSFUT was carried out. the acoustic field pressure distribution nephogram and the axial acoustic pressure curve of the SSFUT were obtained. The consistency of finite element simulation results and experimental results was verified by testing. The research provides a theoretical basis for implementation and application of the new focused ultrasonic technology.

scholarly journals Inertia Controlled Capillary Pressure at the Juncture between Converging and Uniform Channels

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Harris Sajjad Rabbani ◽  
Thomas Daniel Seers
Keyword(s):  
Fluid Dynamics ◽  
Capillary Pressure ◽  
Transient Behavior ◽  
Inertial Forces ◽  
Stability Criteria ◽  
Interface Morphology ◽  
Fluid Interface ◽  
Fundamental Study ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

Abstract In this research, we reveal the transient behavior of capillary pressure as the fluid-fluid interface travels across the juncture between a converging and uniform capillary, via high-resolution CFD (Computational Fluid Dynamics) simulations. Simulations were performed at different wetting conditions (strong-wet and intermediate-wet) and capillary wall convergence angles. Our results demonstrate that as the angle of convergence increases, capillary pressure at the junction decreases commensurately. Moreover, in contrast to strong-wet conditions, the profile of capillary pressure at the converging-uniform capillary juncture under intermediate-wet conditions is highly non-monotonic, being characterized by a parabola-like form. This non-monotonic behavior is a manifestation of strong inertial forces governing dynamic fluid-fluid interface morphology. This yields conditions that promote the advancement of the fluid-fluid interface, as inertial forces partially nullify the capillary pressure required for the immiscible interface to enter the uniform capillary. In addition to numerical analysis detailed above, a novel theoretical stability criteria that is capable of distinguishing between stable (capillary dominated) and unstable (inertia dominated) interfacial regimes at the converging-uniform capillary juncture is also proposed. In summary, this fundamental study offers new insights into the interface invasion protocol, and paves the way for the re-evaluation of capillary junction controlled interfacial dynamics.

Transient Response of a Periodically Supported Cylindrical Shell Immersed in a Fluid Medium

1965 ◽  
Vol 32 (3) ◽  
pp. 562-568 ◽  
Author(s):  
Harry Herman ◽  
J. M. Klosner
Keyword(s):  
Cylindrical Shell ◽  
Integral Transform ◽  
Circular Cylindrical Shell ◽  
Fourier Integral ◽  
Cylindrical Wave ◽  
Acoustic Medium ◽  
Steel Shell ◽  
Fluid Medium ◽  
Wave Approximation ◽  
Fourier Integral Transform

The dynamic response of a periodically simply supported, infinitely long, circular cylindrical shell to a pressure suddenly applied through the surrounding acoustic medium is investigated. The incident particle velocity is zero, and the pressure is assumed to have a harmonic spatial variation parallel to the shell axis. The exact solution is obtained by use of a Fourier integral transform, and the resulting inversion integral is evaluated by numerical and asymptotic integration. Two solutions to the same problem are obtained by using a plane and cylindrical wave approximation for the radiated field. The range of their applicability is investigated. For a steel shell in water ccs2=0.08815 it is found that, when the supports are placed three shell diameters apart, the use of the cylindrical wave approximation results in a 5-percent underestimation of the maximum deflection, while when the supports are placed one sixth of a shell diameter apart, the approximations are invalid.

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