Growth and decay of weak disturbances in visco-elastic arteries

1996 ◽  
Vol 18 (1) ◽  
pp. 27-32
Author(s):  
M. Gaur ◽  
S. K. Rai
Keyword(s):  
Weak Disturbances

Propagation of weak disturbances in the combustion of compressible porous fuels

1991 ◽  
Vol 27 (2) ◽  
pp. 154-161 ◽  
Author(s):  
N. N. Smirnov ◽  
S. I. Safargulova
Keyword(s):  
Weak Disturbances

Numerical simulations of evolution of weak disturbances in vibrationally excited gas

2013 ◽  
Vol 133 (5) ◽  
pp. 3328-3328
Author(s):  
Igor Zavershinskii ◽  
Vlavimir Makaryan ◽  
Nonna Molevich
Keyword(s):  
Numerical Simulations ◽  
Vibrationally Excited ◽  
Weak Disturbances

Propagation of weak disturbances in warm water with air bubbles

2017 ◽  
Vol 12 (1) ◽  
pp. 135-142
Author(s):  
I.I. Vdovenko ◽  
N.N. Vdovenko
Keyword(s):  
Oblique Incidence ◽  
Gas Content ◽  
Gas Mixture ◽  
Pure Liquid ◽  
Harmonic Waves ◽  
Air Bubbles ◽  
Angle Of Incidence ◽  
Reflection And Refraction ◽  
Bubble Sizes ◽  
Weak Disturbances

The features of reflection and refraction of harmonic waves at the interface between a ”pure“ liquid and a liquid with bubbles with a vapor-gas mixture under direct and oblique incidence are studied. A numerical analysis is made of the effect of the initial volumetric gas content αg0 for two initial bubble sizes a0=10–6 m and 10–3 m. The influence of the disturbance frequencies on the reflection and refraction coefficients of sound in direct incidence and on the dependence of the angle of refraction on the angle of incidence is studied.

scholarly journals The ITCZ in the Central and Eastern Pacific on Synoptic Time Scales

2006 ◽  
Vol 134 (5) ◽  
pp. 1405-1421 ◽  
Author(s):  
Chia-chi Wang ◽  
Gudrun Magnusdottir
Keyword(s):  
Life Span ◽  
Time Scales ◽  
Eastern Pacific ◽  
Strong Tendency ◽  
Frequency Of Occurrence ◽  
Central Pacific ◽  
Active Season ◽  
Tropical Depression ◽  
Weak Disturbances

Abstract The ITCZ in the central and eastern Pacific on synoptic time scales is highly dynamic. The active season extends roughly from May through October. During the active season, the ITCZ continuously breaks down and re-forms, and produces a series of tropical disturbances. The life span of the ITCZ varies from several days to 3 weeks. Sixty-five cases of ITCZ breakdown have been visually identified over five active seasons (1999–2003) in three independent datasets. ITCZ breakdown can be triggered by two mechanisms: 1) interaction with westward-propagating disturbances (WPDs) and 2) the vortex rollup (VR) mechanism. Results show that the frequency of occurrence of ITCZ breakdown from these two mechanisms is the same. The VR mechanism may have been neglected because the produced disturbances are rather weak and they may dissipate quickly. The ITCZ shows a strong tendency to re-form within 1–2 days in the same location. The ITCZ may break down via the VR mechanism without any other support, and thus it may continuously generate numerous tropical disturbances throughout the season. There are two main differences between the two mechanisms: 1) The WPDs-induced ITCZ breakdown tends to create one or two vortices that may be of tropical depression strength. The VR-induced ITCZ breakdown generates several nearly equal-sized weak disturbances. 2) The WPDs tend to disturb the ITCZ in the eastern Pacific only. Disturbances generally move along the Mexican coast after shedding off from the ITCZ and do not further disturb the ITCZ in the central Pacific. Therefore, the VR mechanism is observed more clearly and is the dominating mechanism for ITCZ breakdown in the central Pacific.

Propagation of Weak Disturbances in a Gas Subject to Relaxation Effects

1960 ◽  
Vol 27 (2) ◽  
pp. 117-127 ◽  
Author(s):  
FRANKLIN K. MOORE ◽  
WALTER E. GIBSON
Keyword(s):  
Relaxation Effects ◽  
Weak Disturbances

Hydraulic jumps in an incompressible stratified fluid

1976 ◽  
Vol 73 (1) ◽  
pp. 33-47 ◽  
Author(s):  
C. H. Su
Keyword(s):  
Continuous Flow ◽  
Richardson Number ◽  
Vertical Structure ◽  
Stratified Fluid ◽  
Hydraulic Jumps ◽  
Two Dimensional ◽  
Layer Model ◽  
Numerical Examples ◽  
Arbitrary Strength ◽  
Weak Disturbances

A multi-layer model is used to describe a ‘two-dimensional’ continuously stratified fluid. We use a momentum theorem in each layer to derive an ordinary differential equation describing the vertical structure behind a jump. This equation is compared with the corresponding equation for continuous flow. As one would expect from the classical one-layer theory, they are identical up to second order for weak disturbances. The energy change across a jump is also derived. By requiring that energy be lost through a jump, we calculate when a weak jump is possible in general. Algorithms for computing jumps of arbitrary strength are given. To ensure that the flow after the jump is stable and also for a numerical reason to be stated in § 8, we require that the Richardson number after the jump be equal to or greater than S¼S. Numerical examples are given to show the range of parameters within which jumps are possible; the velocity profiles related to different kinds of jumps also appear. Since hydraulic jumps in a continuously stratified fluid have not yet been observed in any laboratory, it should be of interest to verify these calculations experimentally.

Behaviour of a sonic wave in dissociating gases

1988 ◽  
Vol 66 (4) ◽  
pp. 334-337 ◽  
Author(s):  
Arisudan Rai ◽  
M. Gaur
Keyword(s):  
Gas Flow ◽  
Singular Surface ◽  
Hyperbolic Partial Differential Equations ◽  
Growth Equation ◽  
Gas Flows ◽  
Present Communication ◽  
Global Behaviour ◽  
Effective Velocity ◽  
Sonic Wave ◽  
Weak Disturbances

The present communication is devoted to the study of weak solutions of the system of hyperbolic partial differential equations in dissociating gas flows. As an application of the singular surface theory, the law of propagation and the growth equation of a sonic wave are obtained, and the breakdown of a sonic wave is also discussed. It is found that weak disturbances in dissociating gases propagate with the effective velocity of sound relative to the gas flow. The effects of dissociation and the wave geometry on the global behaviour of the wave amplitude are discussed. It is concluded that dissociation has a stabilizing effect on the sonic wave in the sense that either it disallows or delays shock formation. The two cases of diverging and converging waves are discussed separately.

Sign in / Sign up

Export Citation Format

Share Document