Determination of the nonlinear parameter by propagating and modeling finite amplitude plane waves

2006 ◽  
Vol 119 (5) ◽  
pp. 2639-2644 ◽  
Author(s):  
F. Chavrier ◽  
C. Lafon ◽  
A. Birer ◽  
C. Barrière ◽  
X. Jacob ◽  
...  
Keyword(s):  
Plane Waves ◽  
Finite Amplitude ◽  
Nonlinear Parameter

Determination of acoustical nonlinear parameter β of water using the finite amplitude method

Ultrasonics ◽  
2013 ◽  
Vol 53 (5) ◽  
pp. 1012-1019 ◽  
Author(s):  
Cristian Pantea ◽  
Curtis F. Osterhoudt ◽  
Dipen N. Sinha
Keyword(s):  
Finite Amplitude ◽  
Nonlinear Parameter

scholarly journals DETERMINATION OF THE NONLINEAR PARAMETER AND INTERNAL PRESSURE IN A LIQUID BY THE ACOUSTIC METHOD

2021 ◽  
Vol 1 (63) ◽  
pp. 88-94
Author(s):  
Jr. Dudzinskii ◽  
◽  
N. Titova ◽  
N. Manicheva ◽  
A. Zakharova ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Medical Devices ◽  
Harmonic Wave ◽  
Wave Interaction ◽  
Acoustic Method ◽  
Finite Amplitude ◽  
Nonlinear Parameter ◽  
Resonance Frequencies ◽  
Intermolecular Distances

An acoustic method is proposed for assessing the molecular properties of a liquid, determining the nonlinear parameter of liquids from the ratio of the first and second harmonics when the acoustic wave changes, and using this parameter to measure the internal pressure. In addition, the proposed method measures intermolecular distances for the studied liquids. In organ fluids, the effects of sound scattering and wave interaction are enhanced. In body fluids, at the molecular level, there is a small amount of microscopic bubbles. This leads to the appearance of the phenomenon of cavitation. These phenomena can be harmful, but not always. There are devices for biological and pharmaceutical technologies, medical devices that successfully use these effects. The paper presents a functional diagram of the experiment, identifies the oscillograms of acoustic signals of finite amplitude at different distances from the emitter. The same devices based on quartz plates 25 mm in diameter with a resonance frequency of 3 MHz were used as the emitter and receiver. This difference of approximately three times the resonance frequencies of the sensors and the acoustic signal ensures the linearity of the amplitude-frequency response of both sensors. Nonlinear acoustic methods are a global trend in biomedical research, as they open up new opportunities and prospects in the development of medical devices. The appearance of higher harmonics in the curvature of the initial harmonic wave of finite amplitude can be used for express analysis of the physical properties of pure liquids and especially aqueous solutions of organic substances. This method of experimental determination of the nonlinear parameter and internal pressure in a liquid is more convenient than the static one, since it does not require the use of high excess static pressures. The proposed acoustic method gives less error than the dynamic one. The accuracy of such a determination can be sufficient to judge the change in the intermolecular interaction in liquids.

Nonlinear Parameter Imaging with Finite-Amplitude Sound Waves

1986 ◽  
Author(s):  
Y. Nakagawa ◽  
W. Hou ◽  
A. Cai ◽  
N. Arnold ◽  
G. Wade
Keyword(s):  
Finite Amplitude ◽  
Nonlinear Parameter ◽  
Sound Waves

Finite-amplitude convection in the presence of an unsteady shear flow

1995 ◽  
Vol 287 ◽  
pp. 225-249 ◽  
Author(s):  
Philip Hall
Keyword(s):  
Shear Flow ◽  
Critical Size ◽  
Low Frequency ◽  
Nonlinear Effects ◽  
Finite Amplitude ◽  
Present Calculation ◽  
Wide Range ◽  
Prandtl Numbers ◽  
Boussinesq Fluid

The effect of an unsteady shear flow on the planform of convection in a Boussinesq fluid heated from below is investigated. In the absence of the shear flow it is well-known, if non-Boussinesq effects can be neglected, that convection begins in the form of a supercritical bifurcation to rolls. Subcritical convection in the form of say hexagons can be induced by non-Boussinesq behaviour which destroys the symmetry of the basic state. Here it is found that the symmetry breaking effects associated with an unsteady shear flow are not sufficient to cause subcritical convection so the problem reduces to the determination of how the orientations of roll cells are modified by an unsteady shear flow. Recently Kelly & Hu (1993) showed that such a flow has a significant stabilizing effect on the linear stability problem and that, for a wide range of Prandtl numbers, the effect is most pronounced in the low-frequency limit. In the present calculation it is shown that the stabilizing effects found by Kelly & Hu (1993) do survive for most frequencies when nonlinear effects and imperfections are taken into account. However a critical size of the frequency is identified below which the Kelly & Hu (1993) conclusions no longer carry through into the nonlinear regime. For frequencies of size comparable with this critical size it is shown that the convection pattern changes in time. The cell pattern is found to be extremely complicated and straight rolls exist only for part of a period.

scholarly journals Local uniqueness in boundary problems

1970 ◽  
Vol 17 (1) ◽  
pp. 23-36
Author(s):  
M. H. Martin
Keyword(s):  
Incompressible Fluid ◽  
Unit Circle ◽  
Finite Amplitude ◽  
Local Uniqueness ◽  
Boundary Problems ◽  
Infinite Depth ◽  
Image Position

The study of periodic, irrotational waves of finite amplitude in an incompressible fluid of infinite depth was reduced by Levi-Civita (1) to the determination of a functionregular analytic in the interior of the unit circle ρ = 1 and which satisfies the condition

Parametrically excited, standing cross-waves

1988 ◽  
Vol 186 ◽  
pp. 119-127 ◽  
Author(s):  
John Miles
Keyword(s):  
Surface Waves ◽  
Phase Plane ◽  
Evolution Equations ◽  
Plane Waves ◽  
Wave Problem ◽  
Parametrically Excited ◽  
The Cross ◽  
The Stability ◽  
Cross Waves

Luke's (1967) variational formulation for surface waves is extended to incorporate the motion of a wavemaker and applied to the cross-wave problem. Whitham's average-Lagrangian method then is invoked to obtain the evolution equations for the slowly varying complex amplitude of the parametrically excited cross-wave that is associated with symmetric excitation of standing waves in a rectangular tank of width π/k, length l and depth d for which kl = O(1) and kd [Gt ] 1. These evolution equations are Hamiltonian and isomorphic to those for parametric excitation of surface waves in a cylinder that is subjected to a vertical oscillation, for which phase-plane trajectories, stability criteria and the effects of damping are known (Miles 1984a). The formulation and results differ from those of Garrett (1970) in consequence of his linearization of the boundary condition at the wavemaker and his neglect of self-interaction of the cross-waves in the free-surface conditions (although Garrett does incorporate self-interaction in his calculation of the equilibrium amplitude of the cross-waves). These differences have only a small effect on the criterion for the stability of plane waves, but the self-interaction is crucial for the determination of the stability of the cross-waves.

Sign in / Sign up

Export Citation Format

Share Document