Effect of Tube Banks on Rarefaction Wave Propagation

1982 ◽  
Vol 104 (2) ◽  
pp. 102-111
Author(s):  
D. Squarer ◽  
A. E. Manhardt
Keyword(s):  
Wave Propagation ◽  
Rarefaction Wave ◽  
Steam Generator ◽  
Transmission Loss ◽  
Wave Length ◽  
Scale Model ◽  
Free Jet ◽  
Feed Line ◽  
Tube Banks ◽  
Theoretical Considerations

In a continuing effort to study the effect of steam generator feed line break on steam generator internals, a theoretical and experimental study has been undertaken. This paper summarizes results of a study whose goal is to check the effects of tube rows on rarefaction wave propagation generated by a sudden rupture. The effect of the tubes is presented in terms of measured pressures and strains with and without tubes. Ten rows of tubes are found to cause a transmission loss in the 1:10 steam generator scale model smaller than 689 kPa along the feed line centerline and have little effect away from the centerline, or on the pressure difference across the divider plate. Theoretical considerations include: estimating transmission losses in terms of tube bank geometry, wave length and frequency, and incident pulse; reflection from a free jet, and potential flow solution to the flow field near the pressure vessel-feed line interface.

Numerical Study of the Mean and Filtered Characteristics of Turbulent Jets Impinging on Convex and Flat Surfaces Using LES

2012 ◽  
Author(s):  
Adra Benhacine ◽  
Zoubir Nemouchi ◽  
Lyes Khezzar ◽  
Nabil Kharoua
Keyword(s):  
Convex Surface ◽  
Numerical Study ◽  
Three Dimensional ◽  
Turbulent Jets ◽  
Scale Model ◽  
Wall Jet ◽  
Potential Core ◽  
Flat Surfaces ◽  
Free Jet ◽  
Eddy Simulation

A numerical study of a turbulent plane jet impinging on a convex surface and on a flat surface is presented, using the large eddy simulation approach and the Smagorinski-Lilly sub-grid-scale model. The effects of the wall curvature on the unsteady filtered, and the steady mean, parameters characterizing the dynamics of the wall jet are addressed in particular. In the free jet upstream of the impingement region, significant and fairly ordered velocity fluctuations, that are not turbulent in nature, are observed inside the potential core. Kelvin-Helmholtz instabilities in the shear layer between the jet and the surrounding air are detected in the form of wavy sheets of vorticity. Rolled up vortices are detached from these sheets in a more or less periodic manner, evolving into distorted three dimensional structures. Along the wall jet the Coanda effect causes a marked suction along the convex surface compared with the flat one. As a result, relatively important tangential velocities and a stretching of sporadic streamwise vortices are observed, leading to friction coefficient values on the curved wall higher than those on the flat wall.

Period equation for Rayleigh waves in a layer overlying a half space with a sinusoidal interface

1962 ◽  
Vol 52 (4) ◽  
pp. 807-822 ◽  
Author(s):  
John T. Kuo ◽  
John E. Nafe
Keyword(s):  
Wave Propagation ◽  
Boundary Conditions ◽  
Half Space ◽  
Rayleigh Waves ◽  
Wave Length ◽  
Linear Equations ◽  
Wave Number ◽  
Interface Plane ◽  
Period Equation ◽  
Phase And Group Velocities

abstract The problem of the Rayleigh wave propagation in a solid layer overlying a solid half space separated by a sinusoidal interface is investigated. The amplitude of the interface is assumed to be small in comparison to the average thickness of the layer or the wave length of the interface. Either by applying Rayleigh's approximate method or by perturbating the boundary conditions at the sinusoidal interface, plane wave solutions for the equations which satisfy the given boundary conditions are found to form a system of linear equations. These equations may be expressed in a determinant form. The period (or characteristic) equations for the first and second approximation of the wave number k are obtained. The phase and group velocities of Rayleigh waves in the present case depend upon both frequency and distance. At a given point on the surface, there is a local phase and local group velocity of Rayleigh waves that is independent of the direction of wave propagation.

scholarly journals An Insight into Creeping Electromagnetic Waves around the Human Body

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Branimir Ivsic ◽  
Davor Bonefacic ◽  
Zvonimir Sipus ◽  
Juraj Bartolic
Keyword(s):  
Wave Propagation ◽  
Human Body ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Axial Magnetic Field ◽  
Magnetic Dipoles ◽  
Wearable Antennas ◽  
Field Decay ◽  
Theoretical Considerations ◽  
Insight Into

The electromagnetic wave propagation around human body torso is modelled by considering elementary electric and magnetic dipoles over an infinite muscle-equivalent cylinder. The poles in the spectral domain Green’s function with smallest imaginary part are found to correspond to creeping wave propagation coefficients which predict the general trend in propagation around human body. In addition, it was found that axial magnetic field component is crucial for communication via creeping waves since it generates modes with smaller field decay compared to axial electric field. The developed model may thus serve as a practical guideline in design of on-body wearable antennas. The theoretical considerations are verified with simulations and measurements on the prototype of PIFA antenna placed on the human body.

Stability of planar rarefaction wave to the 3D bipolar Vlasov–Poisson–Boltzmann system

2019 ◽  
Vol 30 (01) ◽  
pp. 23-104 ◽  
Author(s):  
Shu Wang ◽  
Teng Wang
Keyword(s):  
Wave Propagation ◽  
Boltzmann Equation ◽  
Asymptotic Stability ◽  
Rarefaction Wave ◽  
Stability Result ◽  
Three Dimensions ◽  
Wave Patterns ◽  
Shock Profiles ◽  
Poisson Boltzmann ◽  
Math Phys

We investigate the time-asymptotic stability of planar rarefaction wave for the 3D bipolar Vlasov–Poisson Boltzmann (VPB) system, based on the micro–macro decompositions introduced in [T. P. Liu and S. H. Yu, Boltzmann equation: Micro–macro decompositions and positivity of shock profiles, Comm. Math. Phys. 246 (2004) 133–179; Energy method for the Boltzmann equation, Physica D 188 (2004) 178–192] and our new observations on the underlying wave structures of the equation to overcome the difficulties due to the wave propagation along the transverse directions and its interactions with the planar rarefaction wave. Note that this is the first stability result of basic wave patterns for bipolar VPB system in three dimensions.

Rarefaction wave propagation in a waveguide in a hydrate-containing porous medium

2019 ◽  
Author(s):  
A. A. Gubaidullin ◽  
O. Yu. Boldyreva ◽  
D. N. Dudko
Keyword(s):  
Porous Medium ◽  
Wave Propagation ◽  
Rarefaction Wave

scholarly journals The rarefaction wave propagation in transparent windows

2017 ◽  
Author(s):  
B. Glam ◽  
E. Porat ◽  
Y. Horovitz ◽  
A. Yosef-Hai
Keyword(s):  
Wave Propagation ◽  
Rarefaction Wave ◽  
Transparent Windows

WAVE PROPAGATION IN A LIQUID LAYER

Geophysics ◽  
1959 ◽  
Vol 24 (4) ◽  
pp. 658-666 ◽  
Author(s):  
D. T. Liu
Keyword(s):  
Wave Propagation ◽  
Wave Equation ◽  
Pressure Wave ◽  
Wave Length ◽  
Water Layer ◽  
Fundamental Wave ◽  
Ray Theory ◽  
Seismic Record ◽  
Amplitude Response ◽  
Oscillatory Phenomenon

In many areas offshore, the conventional seismic record has the appearance of a series of sine waves or simple odd harmonic combinations of sine waves, with a fundamental wave length four times the water depth. Burg, et al., in a ray theory treatment, ascribe this oscillatory phenomenon to guided energy traveling in the water layer. A solution of the pressure wave equation for a point source in the water layer has been obtained. It allows one to examine not only the frequency dependence with the depth, but also the transient amplitude response with depth and time. It is concluded that in most actual situations, the phenomenon cannot be wholly explained by the assumed mechanism, because the theory indicates too rapid a decay of the energy.

Predicting the Sound Transmission Loss of Honeycomb Panels using the Wave Propagation Approach

2011 ◽  
Vol 97 (5) ◽  
pp. 869-876 ◽  
Author(s):  
Sathish Kumar ◽  
Leping Feng ◽  
Ulf Orrenius
Keyword(s):  
Wave Propagation ◽  
Transmission Loss ◽  
Plate Theory ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Structural Vibration ◽  
Sound Transmission Loss ◽  
Resonance Frequencies ◽  
Fluid Coupling ◽  
Vibration And Sound Radiation

The sound transmission properties of sandwich panels can be predicted with sufficient degree of accuracy by calculating the wave propagation properties of the structure. This method works well for sandwich panels with isotropic cores but applications to panels with anisotropic cores are hard to find. Honeycomb is an example of anisotropic material which when used as a core, results in a sandwich panel with anisotropic properties. In this paper, honeycomb panels are treated as being orthotropic and the wavenumbers are calculated for the two principle directions. These calculated wavenumbers are validated with the measured wavenumbers estimated from the resonance frequencies of freely hanging honeycomb beams. A combination of wave propagation and standard orthotropic plate theory is used to predict the sound transmission loss of honeycomb panels. These predictions are validated through sound transmission measurements. Passive damping treatment is a common way to reduce structural vibration and sound radiation, but they often have little effect on sound transmission. Visco-elastic damping with a constraining layer is applied to two honeycomb panels with standard and enhanced fluid coupling properties. This enhanced fluid coupling in one of the test panels is due to an extended coincidence range observed from the dispersion curves. The influence of damping treatments on the sound transmission loss of these panels is investigated. Results show that, after the damping treatment, the sound transmission loss of an acoustically bad panel and a normal panel are very similar.

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