scholarly journals Nonlinear Interaction of Acoustic Waves with a Spheroidal Particle: Radiation Force and Torque Effects

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Everton B. Lima ◽  
José P. Leão-Neto ◽  
Alisson S. Marques ◽  
Giclênio C. Silva ◽  
José H. Lopes ◽  
...  
2018 ◽  
Vol 124 (10) ◽  
pp. 104503 ◽  
Author(s):  
Shen Liang ◽  
Wang Chaohui ◽  
Hu Qiao

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 52 ◽  
Author(s):  
Jin-Chen Hsu ◽  
Chih-Hsun Hsu ◽  
Yeo-Wei Huang

We present a numerical and experimental study of acoustophoretic manipulation in a microfluidic channel using dual-wavelength standing surface acoustic waves (SSAWs) to transport microparticles into different outlets. The SSAW fields were excited by interdigital transducers (IDTs) composed of two different pitches connected in parallel and series on a lithium niobate substrate such that it yielded spatially superimposed and separated dual-wavelength SSAWs, respectively. SSAWs of a singltablee target wavelength can be efficiently excited by giving an RF voltage of frequency determined by the ratio of the velocity of the SAW to the target IDT pitch (i.e., f = cSAW/p). However, the two-pitch IDTs with similar pitches excite, less efficiently, non-target SSAWs with the wavelength associated with the non-target pitch in addition to target SSAWs by giving the target single-frequency RF voltage. As a result, dual-wavelength SSAWs can be formed. Simulated results revealed variations of acoustic pressure fields induced by the dual-wavelength SSAWs and corresponding influences on the particle motion. The acoustic radiation force in the acoustic pressure field was calculated to pinpoint zero-force positions and simulate particle motion trajectories. Then, dual-wavelength SSAW acoustofluidic devices were fabricated in accordance with the simulation results to experimentally demonstrate switching of SSAW fields as a means of transporting particles. The effects of non-target SSAWs on pre-actuating particles were predicted and observed. The study provides the design considerations needed for the fabrication of acoustofluidic devices with IDT-excited multi-wavelength SSAWs for acoustophoresis of microparticles.


2015 ◽  
Vol 29 (4) ◽  
pp. 611-621 ◽  
Author(s):  
Chao-feng Lan ◽  
Feng-chen Li ◽  
Huan Chen ◽  
Di Lu ◽  
De-sen Yang ◽  
...  

2000 ◽  
Vol 62 (11) ◽  
pp. 6948-6951 ◽  
Author(s):  
A. B. Hutchinson ◽  
V. I. Talyanskii ◽  
M. Pepper ◽  
G. Gumbs ◽  
G. R. Aǐzin ◽  
...  

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Manjistha Dutta ◽  
Manoranjan Khan ◽  
Nikhil Chakrabarti

Nonlinear interaction between Langmuir waves and Electron Acoustic Wave (EAW) is being studied in a warm magnetized plasma in presence of two intermingled fluids, hot electrons, and cold electrons while ions forming static background. Two-fluid, two-timescale theory is performed to derive modified Zakharov's equations in a magnetized plasma. These coupled equations describe low-frequency response of electron density due to high-frequency electric field along with magnetic field perturbations. Linear analysis shows coupling between acoustic mode, upper hybrid mode, and cyclotron modes. These modes are found to be modified due to the presence of two electron components. These equations are significant in the context of weak and strong turbulence.


Author(s):  
Sebastian Sachs ◽  
Christian Cierpka ◽  
Jörg König

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.


Author(s):  
S. Wanga ◽  
J. S. Allen ◽  
A. M. Ardekani

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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