Experimental results for transmission of a finite‐amplitude, focused sound beam at a curved interface between two media

1996 ◽  
Vol 100 (4) ◽  
pp. 2589-2589
Author(s):  
Inder Raj S. Makin ◽  
E. Carr Everbach ◽  
Mark F. Hamilton
Keyword(s):  
Finite Amplitude ◽  
Experimental Results ◽  
Sound Beam ◽  
Curved Interface

A more general model equation of nonlinear Rayleigh waves and their quasilinear solutions

2016 ◽  
Vol 30 (08) ◽  
pp. 1650096 ◽  
Author(s):  
Shuzeng Zhang ◽  
Xiongbing Li ◽  
Hyunjo Jeong
Keyword(s):  
Rayleigh Waves ◽  
General Equation ◽  
Wave Motion ◽  
Numerical Solutions ◽  
Second Harmonic ◽  
Approximate Equation ◽  
Finite Amplitude ◽  
Sound Beam ◽  
Quasilinear Theory ◽  
Sound Beams

A more general two-dimensional wave motion equation with consideration of attenuation and nonlinearity is proposed to describe propagating nonlinear Rayleigh waves of finite amplitude. Based on the quasilinear theory, the numerical solutions for the sound beams of fundamental and second harmonic waves are constructed with Green’s function method. Compared with solutions from the parabolic approximate equation, results from the general equation have more accuracy in both the near distance of the propagation direction and the far distance of the transverse direction, as quasiplane waves are used and non-paraxial Green’s functions are obtained. It is more effective to obtain the nonlinear Rayleigh sound beam distributions accurately with the proposed general equation and solutions. Brief consideration is given to the measurement of nonlinear parameter using nonlinear Rayleigh waves.

The evolution of a localized vortex disturbance in external shear flows. Part 1. Theoretical considerations and preliminary experimental results

1995 ◽  
Vol 289 ◽  
pp. 159-177 ◽  
Author(s):  
Vladimir Levinski ◽  
Jacob Cohen
Keyword(s):  
Boundary Layers ◽  
Shear Flows ◽  
Flow Direction ◽  
Linear Equations ◽  
Three Dimensional ◽  
Finite Amplitude ◽  
Experimental Results ◽  
Instability Criterion ◽  
Hairpin Vortices ◽  
Plane Normal

The evolution of a finite-amplitude three-dimensional localized disturbance embedded in external shear flows is addressed. Using the fluid impulse integral as a characteristic of such a disturbance, the Euler vorticity equation is integrated analytically, and a system of linear equations describing the temporal evolution of the three components of the fluid impulse is obtained. Analysis of this system of equations shows that inviscid plane parallel flows as well as high Reynolds number two-dimensional boundary layers are always unstable to small localized disturbances, a typical dimension of which is much smaller than a dimensional length scale corresponding to an O(1) change of the external velocity. Since the integral character of the fluid impulse is insensitive to the details of the flow, universal properties are obtained. The analysis predicts that the growing vortex disturbance will be inclined at 45° to the external flow direction, in a plane normal to the transverse axis. This prediction agrees with previous experimental observations concerning the growth of hairpin vortices in laminar and turbulent boundary layers. In order to demonstrate the potential of this approach, it is applied to Taylor-Couette flow, which has additional dynamical effects owing to rotation. Accordingly, a new instability criterion associated with three-dimensional localized disturbances is found. The validity of this criterion is supported by our experimental results.

QUALITATIVE ANALYSIS OF THE KHOKHLOV–ZABOLOTSKAYA–KUZNETSOV (KZK) EQUATION

2008 ◽  
Vol 18 (05) ◽  
pp. 781-812 ◽  
Author(s):  
ANNA ROZANOVA-PIERRAT
Keyword(s):  
Blow Up ◽  
Viscous Medium ◽  
Finite Amplitude ◽  
Mean Value ◽  
Nonlinear Propagation ◽  
Step Method ◽  
Fractional Step Method ◽  
Sound Beam ◽  
Kzk Equation ◽  
Zero Viscosity

The Khokhlov–Zabolotskaya–Kuznetzov (KZK) equation is considered as a model of nonlinear acoustic which describes the nonlinear propagation of a finite-amplitude focused sound beam which is essentially one-directional, in the thermo-viscous medium.1,7,8 The aim of this paper is the study of the existence, uniqueness, stability, regularity, continuous dependence on the initial value and blow-up of solution of the KZK equation in Sobolev spaces Hs of periodic on x functions and with mean value zero. Existence of shock waves for the model with zero viscosity is proved using S. Alinhac's method.2 Global existence in time of the beam's propagation in viscous media is established for small enough initial data. Existence result is proved by two methods: first by the fractional step method in the particular case ℝ3 and s = 3 to justify the numerical results of Thierry Le Pollès25 and second for the general case ℝn and s > [n/2] + 1 by the approach used in Refs. 12 and 13 for the Kadomtsev–Petviashvili (KP) equation.

Distortion and harmonic generation in the nearfield of a finite amplitude sound beam

1984 ◽  
Vol 75 (3) ◽  
pp. 749-768 ◽  
Author(s):  
Sigurd Ivar Aanonsen ◽  
Tor Barkve ◽  
Jacqueline Naze Tjo/tta ◽  
Sigve Tjo/tta
Keyword(s):  
Harmonic Generation ◽  
Finite Amplitude ◽  
Sound Beam

Dynamical Modeling of Deepwater-Type Cylindrical Tuned Liquid Damper With a Submerged Net

1999 ◽  
Vol 122 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Shigehiko Kaneko ◽  
Yasuo Mizota
Keyword(s):  
Wave Theory ◽  
Finite Amplitude ◽  
Hydrodynamic Forces ◽  
Experimental Results ◽  
Shaking Table ◽  
Cylindrical Tank ◽  
Tuned Liquid Damper ◽  
Amplitude Wave ◽  
Modeling Methodology ◽  
Liquid Depth

An analytical model for describing the effectiveness of a deepwater-type cylindrical tuned liquid damper (TLD) with a submerged net for suppressing horizontal vibration of structures is first proposed. In this study, we performed calculations to estimate the effectiveness of a deepwater-type cylindrical TLD based on a proposed dynamical model and compared with experimental results obtained by shaking table experiments and free oscillation tests. In particular, the effect of hydraulic resistance produced by a submerged net and the liquid depth ratio (the ratio of the liquid depth to the diameter of the cylindrical tank) are examined intensively. In the analysis, employing finite amplitude wave theory and Galerkin method in the case of cylindrical tank, we obtained hydrodynamic forces and the free surface elevations. Then, combining the hydrodynamic forces with the equation of motion of the structure, damped transient responses were calculated. The calculated results thus obtained were compared with the experimental results, by which the validity of the modeling methodology was confirmed. [S0094-9930(00)00101-3]

scholarly journals Directional Loudspeaker Using a Parametric Array

10.14311/862 ◽  
2006 ◽  
Vol 46 (4) ◽  
Author(s):  
A. Ritty
Keyword(s):  
Carrier Frequency ◽  
Nonlinear Acoustics ◽  
Finite Amplitude ◽  
Sound Beam ◽  
Sound Reproduction ◽  
Audible Sound ◽  
Parametric Array ◽  
Film Transducer

The theory for sound reproduction of parametric arrays is based on nonlinear acoustics. Due to the nonlinearity of the air, a finite amplitude ultrasound interacts with itself and generates audible secondary waves in the sound beam. A special feature of this loudspeaker is its sharper directivity compared to conventional loudspeakers of the same aperture size.This paper describes the basis of the theory used for parametric arrays, and presents the influence of the main parameters, e.g., carrier frequency. It also describes some signal pre-processing needed to obtain the desired audible sound. A PVDF (polyvinylidenefluoride) film transducer is also studied in order to produce a prototype to confirm the theory. 

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