Acoustical scattering from an elastic sphere in water

surface wave glory, resonances, and the Sommerfeld-Watson transformation for amplitudes by Kevin Lee Williams

Written in English
Published: Pages: 161 Downloads: 840
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Subjects:

  • Sound-waves -- Scattering.,
  • Underwater acoustics.

Edition Notes

Statementby Kevin Lee Williams.
The Physical Object
Paginationxi, 161 leaves, bound :
Number of Pages161
ID Numbers
Open LibraryOL16974194M

  Acoustic radiation force on solid elastic sphere in cylindrical cavity is derived. • The effect of a cavity on radiation force is studied for different relative radii. • The acoustic radiation force for a sphere with different materials is analyzed. • The relationship between negative forces and backscattering is discussed. The transition matrix, relating the scattered and incident acoustic waves, for a thin elastic spherical shell in a free-field environment, has been evaluated using the ATILA finite-element code.   Two experiments to measure the size of microscopic dielectric spherical particles immersed in purified water with spheres of a nominal diameter ± μm have been carried out in order to revisit Mie scattering first experiment uses a 1 mW helium–neon (He–Ne) laser with a wavelength of nm, while the second one is carried out using a diode laser of nm. Key words: acoustics, multiple scattering, elastic spheres, resonant coupling. 1. ACOUSTIC SCATTERING BY TWO SPHERES Let us suppose a harmonic plane wave incident on a system of two spheres embedded in water. This wave propagates in the (x, z) plane, under angle α with respect to the Oz axis. Fig. 1 shows the geometry of the problem.

Scattering of sound - Part II- scattering from a sphere The problem: •An incident plane-parallel wave •Possible absorption •A scattered wave Scattering: combined action of reflection, refraction and diffraction from objects with differing sound speed. Medwin et al., References. Request PDF | Cancellation of acoustic scattering from an elastic sphere | Recent research has suggested the possibility of creating acoustic cloaks using metamaterial layers to eliminate the. Acoustic scattering experiments are described in the time domain, and on the basis of the Wigner-Ville distribution. Acoustic propagation in the water column over elastic boundaries is studied experimentally both in laboratory tanks, and in the field, and is analyzed theoretically. Acoustic propagation in the water column over elastic boundaries is studied experimentally both in laboratory tanks, and in the field, and is analyzed theoretically. Ultrasonic nondestructive testing, including such aspects like probe modelling, scattering by various types of cracks, receiving probes and calibration by a side-drilled hole is.

  The calculation results for the acoustic radiation function of the elastic stainless steel sphere and brass sphere are shown in Figures 8 and 9, is found that the Y p − k a curves have a series of prominent peaks and dips corresponding to resonant frequencies of the elastic oscillation of the sphere. For a stainless steel sphere, there is a flat region at 2. Then, the known expression for scattering of a plane wave from an elastic sphere (i.e., the spherical harmonics series) is applied for each plane-wave component of the incident field. The net scattered field is expressed as a superposition of the scattered fields . We study the problem of scattering of acoustic pulses on a rigid sphere located near the interface of two media in one of which (the bottom) sound absorption is taken into account. To find the amplitudes of the echo-signal in the distal field we apply the Fourier transform with . The intent of this book is to make accessible selected reflection- and -reflection-related work of a group that has been conducting such research since approximately Contents: Approximate Formulation of Reflection by the Summation Formula; Reflection from a Finite Plane and Experimental Measurement; Theory and Demonstration of Creeping Waves; Circumferential Wave Interpretations in.

Acoustical scattering from an elastic sphere in water by Kevin Lee Williams Download PDF EPUB FB2

The scattering of acoustical waves from fluid -load elastic spheres with 10 acoustic wave in the liquid and a the radius of the sphere) is studied.

The main emphasis is on understanding the scattered pressure near by: 1. elastic constants and the density as obtained in our laboratory for the Ti-Al-V alloy. We are going to look at ~ and ~ diameter spheres and consider three scattering cases.

They are a cavity which is basically a vacuum, a tungsten carbide sphere, and a magnesium sphere. The tungstenCited by: 1. The elastic properties of the cylinder and the sphere and the viscosity of the surrounding fluid are taken into account in the solution of the acoustic‐scattering problems.

The associated acoustic quantities, such as the acoustic‐scattering patterns, the acoustic‐radiation forces, and the acoustic attenuation, are first derived in closed forms and then evaluated numerically for Acoustical scattering from an elastic sphere in water book given set of material properties.

Cited by: The classical normal-mode series of acoustic scattering from solid elastic cylinders and spheres is reformulated in terms of the S-function as developed in nuclear scattering theory.

It is then subjected to the Watson transformation, which permits an evaluation of the scattering amplitude at its potes ("Regge potes") and saddle. An elastic body of spherical shape is the only one of all three-dimensional objects for which the exact solution of acoustic wave scattering can be obtained.

Therefore, the problem of scattering from an elastic sphere has attracted the attention of investigators for a long : Naum D. Veksler, Herbert Überall. Theoretical and experimental studies of the scattering of compressional waves from an elastic sphere imbedded in an isotropic elastic medium have been carried out by the authors; the experiments were performed with impulsive signals.

Both monostatic and bistatic scattering amplitudes were obtained. In this chapter, the steady-state problem of an incident plane acoustic wave scattered by an infinitely long elastic cylinder and by a sphere immersed in a liquid are considered.

An analysis of the influence of the longitudinal (c l) and transverse (c t) velocities in the material of the scatterer on the form function and on the properties of the peripheral waves is presented.

The Sommerfeld–Watson transformation (SWT) of the partial wave series for the acoustical scattering from a fluid‐loaded elastic sphere is examined.

This research specifically focuses on the specular reflection and Rayleigh wave contribution to scattering at small backscattering angles.

In a previous paper the angular dependence of the Rayleigh contribution to near backward scattering. Abstract. The scattering of acoustic waves by an elastic sphere in a shallow ocean wave guide is investigated taking into account the shear waves which can exist in addition to compressional waves in scatterers of solid material.

Expressions for the scattered waves are given. The exact partial wave series for the scattering by a sphere centered on an ideal Bessel beam was recently given by Marston [“Scattering of a Bessel beam by a sphere,” J. Acoust. Soc.– ()]. That series is applied here to solid elastic spheres in water and to an empty.

Cross sections are computed for the scattering of a plane transverse elastic wave by an elastic sphere in an infinite isotropic homogeneous elastic solid. Analytic expressions are derived for the matrix elements indicated by Einspruch, Witterholt, and Truell, and the resulting matrix equations are solved numerically.

The dependence of the scattering cross section upon K 1 a (K 1 is the. Book Search tips Selecting this option will search all publications across the Scitation platform Selecting this option will search all publications for the Publisher/Society in context.

Acoustic Rayleigh scattering in water-saturated granular medium with quasicrystalline approximation Based on scattering theory for an elastic sphere, 2. sound in the surrounding water, and is a a characteristic target dimension such as radius.

In this study, acoustic plane wave scattering from a variety of rigid and elastic targets in water was considered in the time domain. Plane waves were chosen as the incident pressure field to simulate the effect of a far field point source.

Results were. Acoustic scattering by two identical spheres is theoretically, numerically and experimentally studied by highlighting the role of the symmetries of the scatterer. Incident and scattered fields are expanded over the different irreducible representations of D ∞ h, the continuous symmetry group of the scatterer.

Literature shows solutions to a Gaussian acoustic beam scattered by spherical particles underwater [ 11 ], a Bessel acoustic beam interacting with a rigid sphere [ 12] and the multiple scattering of cylindrical rods encased in a solid viscoelastic medium [ 13] for example.

The problem of the scattering of a plane sound wave by a homogeneous elastic sphere with a radially inhomogeneous coating is considered. An analytical description of the acoustic field scattered. attention in the literature.

The first study of sound wave scattering from elastic spheres and cylinders was given by Faran [1], and dealt with normally incident compressional waves on a submerged, elastic, isotropic and homogeneous sphere, or an infinitely long rod.

A normal mode expansion technique was used, which since has become the basis. The scattering nature of a lucite body is of particular significance as it is typically used in NDE experiments as a host material with embedded inclusions. Figures (4b) and (4c) respectively present the field for an aluminum sphere in water and a brass sphere in glycerine at a higher frequency (ka=).

Acoustic scattering by elastic spheres in water has been widely investigated [1][2] [3] [4] in the last 40 years. However, these studies are mostly concerned with an infinite medium, the case when.

Abstract. We present here the results of applying resonance scattering theory to the problem of a plane acoustic wave scattering from a spherical shell with moderate thickness (with h = 1/32) and from a thick-walled shell (with h = 1/10).

The computations have been carried out and analyzed in a broad frequency band (0 ≤ x ≤ ) and for large orders of resonances (n ≲ ). The scattering of acoustic waves by an elastic sphere embedded in an elastic isotropic medium is investigated.

Expressions for the scattered waves are given in terms of monostatic and bistatic. The scattering of acoustic waves by a chain of elastic spheres in liquid is studied. The incident wave, the scattering wave in the host, and the transmitted waves (including longitudinal and transverse wave modes) in the elastic spheres are all expanded in the form of a series of spherical wave functions.

The scattering of acoustic waves by an elastic sphere in a shallow ocean wave guide is investigated taking into account the shear waves which can exist in addition to compressional waves in scatterers of solid material.

Expressions for the scattered waves are given. Numerical values for a quantity called the farfield form function for various depth are presented in graphical forms. An analysis of the scattering of transverse elastic waves by spherical obstacles is presented. The scatterer is taken to be (a) a cavity, (b) a rigid sphere, (c) a fluid‐filled cavity, and (d) to consist of an elastic material with properties different from those of the surrounding material.

The problems are carried as far as possible analytically without approximations and are reported as. The exact acoustic scattering by a sphere centered along the propagation axis of a HOBB is expressed as a partial wave series involving the scattering polar angle θ relative to the beam axis, the half-cone angle β of the wave vector components of the HOBB, and the azimuthal angle ϕ.

longitudinal wave by three different obstacles - an isotropically elastic sphere, a spherical cavity, and a rigid sphere. Hickling [5] studied the scattering by solid elastic spheres in water.

Doolittle and Uberall extended this to elastic cylinders [6], Recently, the NDE (Non Destructive Evaluation) community has shown considerable ('. Scattering by a spherical obstacle of a plane longitudinal wave propagating in an isotropically elastic solid is computed.

Expressions for the scattered wave and the total scattered energy are given. Three special types of obstacle—an isotropically elastic sphere, a spherical cavity, and a rigid sphere—are discussed in detail, especially for Rayleigh scattering. Pioneering development of acoustic resonance scattering theory.

Channeling in under-ocean sound propagation. Elastic waves: First development of theory of resonance scattering by cavities and inclusions in solids. Electromagnetic waves: Establishment of the relation between resonance scattering theory and the Singularity Expansion Method (SEM).

The acoustic radiation force on the elastic sphere caused by a harmonic wave is defined as a time-averaged quantity over the period T, and is calculated by integrating the mean excess pressure over the surface of the sphere. Since the force is evaluated with accuracy up to second-order terms, it is therefore sufficient to integrate second-order.

The exact analytical solution for the scattering of a generalized (or "hollow") acoustic Bessel beam in water by an elastic sphere centered on the beam is presented.

The far-field acoustic scattering field is expressed as a partial wave series involving the scattering angle relative to the beam axis and the half-conical angle of the wave vector components of the generalized Bessel beam. Fluid, elastic and viscoelastic spheres immersed in water are treated as examples.

Results indicate the capability of manipulating spherical targets based on their mechanical and acoustical properties. This condition provides an impetus for further designing acoustic tweezers operating with standing or quasi-standing Bessel acoustic waves.

Near-field acoustic resonance scattering of a finite bessel beam by an elastic sphere Abstract: The near-field acoustic scattering from a sphere centered on the axis of a finite Bessel acoustic beam is derived stemming from the Rayleigh-Sommerfeld diffraction surface integral and the addition theorems for the spherical wave and Legendre functions.The exact analytical solution for the scattering of a generalized (or “hollow”) acoustic Bessel beam in water by an elastic sphere centered on the beam is presented.