On the Calculation of Radiation Force on Spheres Due to Arbitrary Spatially Distributed Acoustic Beams

2005 ◽  
Author(s):  
Glauber T. Silva ◽  
Mostafa Fatemi
Keyword(s):  
Acoustic Radiation ◽  
Scattering Problem ◽  
Plane Waves ◽  
Acoustic Scattering ◽  
Radiation Force ◽  
Solid Sphere ◽  
Force Function ◽  
Cross Section Area ◽  
Spatially Distributed ◽  
Sphere Radius

This work presents a theory for the acoustic radiation force exerted on a solid sphere by an arbitrary spatially distributed beam. The theory is developed for an sphere suspended in an ideal fluid. We assume that the acoustic beam can be decomposed in a set of plane waves with same frequency, propagating in different directions. The sphere radius is considered to be much smaller than the wavelength of the beam. Bulk properties of the sphere such as shear and compressional sound speed are taken into account. The radiation force is obtained by solving the linear acoustic scattering problem for the sphere. Theoretically, the radiation force depends on the sphere cross section area, the radiation force function, and the vector energy flux upon the sphere. The radiation force function is related to the sphere scattering properties. We apply the developed theory to study the radiation force produced by an spherical concave transducer. The generated radiation force can be decomposed into two components, namely, axial and transverse with respect to the wave propagation direction. The ratio between the transverse and axial components of the force depends on the transducer F-number and wave frequency. Results show that this ratio for a 2 MHz transducer with 3.5 F-number on the focal plane is less than 5%.

Acoustic Scattering and Radiation Force Function Experienced by Functionally Graded Cylindrical Shells

2011 ◽  
Vol 27 (2) ◽  
pp. 227-243 ◽  
Author(s):  
J. Jamali ◽  
M.H. Naei ◽  
F. Honarvar ◽  
M. Rajabi
Keyword(s):  
Acoustic Radiation ◽  
Micromechanical Model ◽  
Acoustic Scattering ◽  
Sound Field ◽  
Radiation Force ◽  
Functionally Graded ◽  
Force Function ◽  
Dynamical Response ◽  
Shell Wall ◽  
Wide Range

ABSTRACTA body insonified by a sound field is known to experience a steady force that is called the acoustic radiation force. In this paper, the method of wave function expansion is adopted to study the scattering and the radiation force function caused by a plane normal harmonic acoustic wave incident upon an arbitrarily thick-walled functionally graded cylindrical shell submerged in and filled with compressible ideal fluids. A laminate approximate model and the so-called state space formulation in conjunction with the classical transfer matrix (T-matrix) approach are employed to present an analytical solution based on the two-dimensional exact equations of elasticity. Two typical models, representing the elastic properties of FGM interlayer, are considered. In both models, the mechanical properties of the graded shell are assumed to vary smoothly and continuously with the change of volume concentrations of the constituting materials across the thickness of the shell. In the first model, the simple rule of mixture governs. In the second, an elegant self-consistent micromechanical model which assumes an interconnected skeletal microstructure in the graded region is employed. Particular attention is paid on dynamical response of these models in a wide range of frequency and for different shell wall-thicknesses. In continue, by focusing on the second model, the normalized radiation force function and the form function amplitude are calculated and compared for different shell wall thicknesses and various profile of variations. Limiting cases are considered and good agreements with the solutions available in the literature are obtained.

Acoustic Scattering Cross Sections of Smart Obstacles: A Case Study

2011 ◽  
Vol 10 (3) ◽  
pp. 672-694
Author(s):  
Lorella Fatone ◽  
Maria Cristina Recchioni ◽  
Francesco Zirilli
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Space Shuttle ◽  
Scattering Problem ◽  
Plane Waves ◽  
Acoustic Scattering ◽  
Scattering Cross Section ◽  
Scattering Cross ◽  
Scattering Cross Sections

AbstractAcoustic scattering cross sections of smart furtive obstacles are studied and discussed. A smart furtive obstacle is an obstacle that, when hit by an incoming field, avoids detection through the use of a pressure current acting on its boundary. A highly parallelizable algorithm for computing the acoustic scattering cross section of smart obstacles is developed. As a case study, this algorithm is applied to the (acoustic) scattering cross section of a “smart” (furtive) simplified version of the NASA space shuttle when hit by incoming time-harmonic plane waves, the wavelengths of which are small compared to the characteristic dimensions of the shuttle. The solution to this numerically challenging scattering problem requires the solution of systems of linear equations with many unknowns and equations. Due to the sparsity of these systems of equations, they can be stored and solved using affordable computing resources. A cross section analysis of the simplified NASA space shuttle highlights three findings: i) the smart furtive obstacle reduces the magnitude of its cross section compared to the cross section of a corresponding “passive” obstacle; ii) several wave propagation directions fail to satisfactorily respond to the smart strategy of the obstacle; iii) satisfactory furtive effects along all directions may only be obtained by using a pressure current of considerable magnitude. Numerical experiments and virtual reality applications can be found at the website: http://www.ceri.uniromal.it/ceri/zirilli/w7.

scholarly journals Inter-Particle Effects with a Large Population in Acoustofluidics

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 101
Author(s):  
Kun Jia ◽  
Yulong Wang ◽  
Liqiang Li ◽  
Jian Chen ◽  
Keji Yang
Keyword(s):  
Rayleigh Scattering ◽  
Acoustic Radiation ◽  
Large Population ◽  
Scattering Problem ◽  
Relative Size ◽  
Radiation Force ◽  
Mie Scattering ◽  
Separation Distance ◽  
High Concentration ◽  
Theoretical Understanding

The ultrasonic manipulation of cells and bioparticles in a large population is a maturing technology. There is an unmet demand for improved theoretical understanding of the particle–particle interactions at a high concentration. In this study, a semi-analytical method combining the Jacobi–Anger expansion and two-dimensional finite element solution of the scattering problem is proposed to calculate the acoustic radiation forces acting on massive compressible particles. Acoustic interactions on arrangements of up to several tens of particles are investigated. The particle radius ranges from the Rayleigh scattering limit (ka«1) to the Mie scattering region (ka≈1). The results show that the oscillatory spatial distribution of the secondary radiation force is related to the relative size of co-existing particles, not the absolute value (for particles with the same radius). In addition, the acoustic interaction is non-transmissible for a group of identical particles. For a large number of equidistant particles arranged along a line, the critical separation distance for the attraction force decreases as the number of particles increases, but eventually plateaus (for 16 particles). The range of attraction for the formed cluster is stabilized when the number of aggregated particles reaches a certain value.

Performance and Robustness Improvements in Ultrasonic Transportation Against Large-Scale Streaming

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Kun Jia ◽  
Ke-ji Yang ◽  
Bing-Feng Ju
Keyword(s):  
Elastic Constant ◽  
Lead Zirconate Titanate ◽  
Large Scale ◽  
Acoustic Radiation ◽  
Plane Waves ◽  
Acoustic Streaming ◽  
Sound Field ◽  
Radiation Force ◽  
Lead Zirconate ◽  
Potential Well

Acoustic streaming generated from the traveling-wave component of a synthesized sound field often has considerable influence on ultrasonic manipulations, in which the behavior of microparticles may be disturbed. In this work, the large-scale streaming pattern in a chamber with three incident plane waves is simulated, illustrating a directional traveling stream pattern and several vortical structures. Based on the numerical results, the trapping capability of an acoustic potential well is quantitatively characterized according to several evaluation criteria: the boundary and elastic constant of the acoustic potential well, the acoustic radiation force offset ratio, and the elastic constant offset ratio. By optimizing these parameters, the constraint of the acoustic potential well can be strengthened to promote the performance and robustness of the ultrasonic transportation. An ultrasonic manipulation device employing three 1.67-MHz lead zirconate titanate (PZT) transducers with rectangular radiation surface is prototyped and performance tested. The experimental results show that the average fluctuations of a microparticle during transportation have been suppressed into a region less than 0.01 times the wavelength. Particle displacement from equilibrium is no longer observed.

scholarly journals Measurements of acoustic radiation force of ultrahigh frequency ultrasonic transducers using model-based approach

2021 ◽  
Author(s):  
Sangnam Kim ◽  
Sunho Moon ◽  
Sunghoon Rho ◽  
Sangpil Yoon
Keyword(s):  
Single Cell ◽  
Acoustic Radiation ◽  
Ultrasonic Transducer ◽  
Radiation Force ◽  
Solid Sphere ◽  
Acoustic Radiation Force ◽  
Ultrasonic Transducers ◽  
Ultrahigh Frequency ◽  
Cell Phenotype ◽  
Target Cells

AbstractEven though ultrahigh frequency ultrasonic transducers over 60 MHz have been used for single cell level manipulation such as intracellular delivery, acoustic tweezers, and stimulation to investigate cell phenotype and cell mechanics, no techniques have been available to measure actual acoustic radiation force (ARF) applied to target cells. Therefore, we have developed an approach to measure ARF of ultrahigh frequency ultrasonic transducers using theoretical model of the dynamics of a solid sphere in a gelatin phantom. To estimate ARF at the focus of 130 MHz transducer, we matched measured maximum displacements of a solid sphere with theoretical calculations. We selected appropriate ranges of input voltages and pulse durations for single cell applications and estimated ARF were in the range of tens of pN to nN. FRET live cell imaging was demonstrated to visualize calcium transport between cells after a target single cell was stimulated by the developed ultrasonic transducer.

Acoustic Scattering

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Acoustic Waves ◽  
Acoustic Radiation ◽  
Scattering Amplitude ◽  
Medical Physics ◽  
Plane Waves ◽  
Acoustic Scattering ◽  
Radiation Condition ◽  
Optical Theorem ◽  
Rigid Sphere ◽  
Symmetric Geometry

This chapter focuses on the mathematics underlying the scattering of acoustic waves. Scattering of waves and/or particles is a common phenomenon. The scattering of plane waves from spheres is applied in a wide array of fields, from optics and acoustics to meteorology, elasticity, seismology, medical physics, quantum mechanics, and biochemistry. With respect to the problem of electromagnetic wave scattering from a sphere, Lorenz found the complete mathematical solution in 1890 in terms of an infinite series of so-called partial waves. The solution is known as the Mie or Debye-Mie solution. The chapter first considers scattering by a cylinder and time-averaged energy flux before discussing spherically symmetric geometry, taking into account the scattering amplitude, the optical theorem, and the Sommerfeld radiation condition. It also examines the case of a rigid sphere, acoustic radiation from a rigid pulsating sphere, the sound of mountain streams, and mathematical bubbles.

scholarly journals DIRECT AND INVERSE ACOUSTIC SCATTERING BY A COMBINED SCATTERER

2015 ◽  
Vol 20 (3) ◽  
pp. 422-442
Author(s):  
Jing Jin ◽  
Jun Guo ◽  
Mingjian Cai
Keyword(s):  
Inhomogeneous Medium ◽  
Sampling Method ◽  
Scattering Problem ◽  
Plane Waves ◽  
Acoustic Scattering ◽  
Uniqueness Result ◽  
Field Pattern ◽  
Linear Sampling Method ◽  
Far Field Pattern ◽  
Linear Sampling

This paper is concerned with the scattering problem of time-harmonic acoustic plane waves by a union of a crack and a penetrable inhomogeneous medium with compact support. The well-posedness of the direct problem is established by the variational method. An uniqueness result for the inverse problem is proved, that is, both the crack and the inhomogeneous medium can be uniquely determined by a knowledge of the far-field pattern for incident plane waves. The linear sampling method is employed to recover the location and shape of the combined scatterer. It is worth noting that we make the first step on reconstructing a mixed-type scatterer of a crack and an inhomogeneous medium by the linear sampling method.

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