Radiation force on a spherical object in an axisymmetric wave field and its application to the calibration of high‐frequency transducers

1996 ◽  
Vol 99 (2) ◽  
pp. 713-724 ◽  
Author(s):  
Xucai Chen ◽  
Robert E. Apfel
Keyword(s):  
Wave Field ◽  
High Frequency ◽  
Radiation Force ◽  
Spherical Object ◽  
Axisymmetric Wave

scholarly journals Research of the process of vegetable oil extracting under the influence of a high frequency wave field

2020 ◽  
Vol 941 ◽  
pp. 012052
Author(s):  
V Yu Ovsyannikov ◽  
A A Berestovoy ◽  
N N Lobacheva ◽  
V V Toroptsev ◽  
S A Trunov
Keyword(s):  
Wave Field ◽  
Vegetable Oil ◽  
High Frequency ◽  
Frequency Wave ◽  
High Frequency Wave

High-Frequency Response of an Elastic Spherical Shell

1969 ◽  
Vol 36 (4) ◽  
pp. 859-864 ◽  
Author(s):  
David Feit ◽  
M. C. Junger
Keyword(s):  
Spherical Shell ◽  
Flat Plate ◽  
Wave Field ◽  
Classical Solution ◽  
High Frequency ◽  
Natural Frequencies ◽  
Near Field ◽  
Flexural Wave ◽  
High Frequency Response ◽  
Field Response

The classical solution of the point-excited spherical shell, in the form of a normal-mode series, converges poorly for large frequencies. By applying the Watson-Sommerfeld transformation to this series, the response is expressed as a sum of only two terms. These terms can be interpreted, respectively, as the near-field response and propagating flexural wave field of an infinite flat plate, the latter term being multiplied by a factor whose maxima coincide with the natural frequencies of the shell.

New model for acoustic waves propagating through a vortical flow

2017 ◽  
Vol 823 ◽  
pp. 658-674 ◽  
Author(s):  
Jim Thomas
Keyword(s):  
Asymptotic Analysis ◽  
Wave Field ◽  
Time Scale ◽  
Acoustic Waves ◽  
High Frequency ◽  
Spatial Scales ◽  
Amplitude Equation ◽  
Vortical Flow ◽  
Reduced Model ◽  
Scale Separation

A new amplitude equation is derived for high-frequency acoustic waves propagating through an incompressible vortical flow using multi-time-scale asymptotic analysis. The reduced model is derived without an explicit spatial-scale separation ansatz between the wave and vortical fields. As a consequence, the model is seen to capture very well the features of the wave field in the regime where the spatial scales of the wave and vortical fields are comparable, a regime for which an optimal reduced model does not seem to be available.

Detection of Contact-Type Damages by Utilizing Nonlinear Piezoelectric Impedance Modulation of Self-Excited Structures

2013 ◽  
Author(s):  
Arata Masuda ◽  
Yuya Ogawa ◽  
Akira Sone
Keyword(s):  
Damage Detection ◽  
Wave Field ◽  
High Frequency ◽  
Detection Method ◽  
Piezoelectric Sensor ◽  
Frequency Wave ◽  
Contact Type ◽  
Impedance Modulation ◽  
Excited Oscillation ◽  
Piezoelectric Impedance

This paper presents an improvement of a nonlinear piezoelectric impedance modulation (NPIM)-based damage detection method, a damage-sensitive, baseline-free structural health monitoring technique proposed by the authors, by introducing self-excited oscillation. The NPIM-based damage detection utilizes the modulation of high-frequency wave field of structures caused by the contact acoustic nonlinearity at the damaged part. In this study, the high-frequency wave field is induced as a self-excited oscillation of the structure by positively feed-backing the strain signal measured by a surface-bonded piezoelectric sensor, followed by a phase-shift in 90 degrees and a nonlinear element consisting of a saturation element and a negative linear gain. The induced self-excitation can have multiple stable limit cycles at certain eigenmode frequencies, and one can switch among them by inputting an auxiliary excitation signal into the feedback loop. The current flowing through the piezoelectric sensor is measured to detect its modulation due to the stiffness fluctuation due to the existence of the contact-type damage. Experiments using a specimen with a simulated damage are conducted to examine the performance of the self-excitation circuit and its applicability to the NPIM-based damage detection method.

scholarly journals Measurement of the acoustic streaming pattern in a standing surface acoustic wave field

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Sebastian Sachs ◽  
Christian Cierpka ◽  
Jörg König
Keyword(s):  
Wave Field ◽  
Acoustic Waves ◽  
Acoustic Radiation ◽  
Electrical Power ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Radiation Force ◽  
Flow Measurements

The application of standing surface acoustic waves (sSAW) has enabled the development of many flexible and easily scalable concepts for the fractionation of particle solutions in the field of microfluidic lab-ona-chip devices. In this context, the acoustic radiation force (ARF) is often employed for the targeted manipulation of particle trajectories, whereas acoustically induced flows complicate efficient fractionation in many systems [Sehgal and Kirby (2017)]. Therefore, a characterization of the superimposed fluid motion is essential for the design of such devices. The present work focuses on a structural analysis of the acousticallyexcited flow, both in the center and in the outer regions of the standing wave field. For this, experimental flow measurements were conducted using astigmatism particle tracking velocimetry (APTV) [Cierpka et al. (2010)]. Through multiple approaches, we address the specific challenges for reliable velocity measurements in sSAW due to limited optical access, the influence of the ARF on particle motion, and regions of particle depletion caused by multiple pressure nodes along the channel width and height. Variations in frequency, channel geometry, and electrical power allow for conclusions to be drawn on the formation of a complex, three-dimensional vortex structure at the beginning and end of the sSAW.

scholarly journals Unsteady particle motion in an acoustic standing wave field

2019 ◽  
Author(s):  
S. Wanga ◽  
J. S. Allen ◽  
A. M. Ardekani
Keyword(s):  
Wave Field ◽  
Standing Wave ◽  
Particle Motion ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Particle Interaction ◽  
Inertial Force ◽  
Radiation Force ◽  
Acoustic Standing Wave ◽  
Standing Wave Field

The acoustic-based separation has attracted considerable attention in biomedical research, such as sorting of cells and particles. Current design principles used for acoustic systems are based on the steady Stokes theory, equating the Stokes drag with the primary radiation force. However, this approach is not valid for large cells/particles or in the presence of particle–particle interaction. In this work,we analytically examine unsteady inertial affects and particle–particle hydrodynamic interaction on the particle motion in a viscous fluid in the presence of an acoustic standing wave field. Comparing our results to the steady Stokes theory, we find that the unsteady inertial force decreases the particle’s velocity, while particle–particle interaction enhances it. For a particular acoustic-based separation approach ‘tilted-angle standing surface acoustic waves (taSSAW)’, we find that both effects of unsteady inertial force and particle–particle interaction are evident and should be considered for O(10μm) particles or larger. Our study improves the current predictions of particle trajectory in acoustic-based separation devices.

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