Acoustic streaming generated by standing waves in two-dimensional channels of arbitrary width

2003 ◽  
Vol 113 (1) ◽  
pp. 153-160 ◽  
Author(s):  
Mark F. Hamilton ◽  
Yurii A. Ilinskii ◽  
Evgenia A. Zabolotskaya
Wave Motion ◽  
2013 ◽  
Vol 50 (5) ◽  
pp. 955-963 ◽  
Author(s):  
Virginie Daru ◽  
Diana Baltean-Carlès ◽  
Catherine Weisman ◽  
Philippe Debesse ◽  
Gurunath Gandikota

2022 ◽  
Vol 933 ◽  
Author(s):  
C. Vargas ◽  
I. Campos-Silva ◽  
F. Méndez ◽  
J. Arcos ◽  
O. Bautista

In this work, a semianalytic solution for the acoustic streaming phenomenon, generated by standing waves in Maxwell fluids through a two-dimensional microchannel (resonator), is derived. The mathematical model is non-dimensionalized and several dimensionless parameters that characterize the phenomenon arise: the ratio between the oscillation amplitude of the resonator and the half-wavelength ( $\eta =2A/\lambda _{a}$ ); the product of the fluid relaxation time times the angular frequency known as the Deborah number ( $De=\lambda _{1}\omega$ ); the aspect ratio between the microchannel height and the wavelength ( $\epsilon =2 H_{0}/\lambda _{a}$ ); and the ratio between half the height of the microchannel and the thickness of the viscous boundary layer ( $\alpha =H_{0}/\delta _{\nu }$ ). In the limit when $\eta \ll 1$ , we obtain the hydrodynamic behaviour of the system using a regular perturbation method. In the present work, we show that the acoustic streaming speed is proportional to $\alpha ^{2.65}De^{1.9}$ , and the acoustic pressure varies as $\alpha ^{6/5}De^{1/2}$ . Also, we have found that the growth of inner vortex is due to convective terms in the Maxwell rheological equation. Furthermore, the velocity antinodes show a high dependency on the Deborah number, highlighting the fluid's viscoelastic properties and the appearance of resonance points. Due to the limitations of perturbation methods, we will only analyse narrow microchannels.


2010 ◽  
Vol 645 ◽  
pp. 411-434 ◽  
Author(s):  
PETER GUBA ◽  
M. GRAE WORSTER

We study nonlinear, two-dimensional convection in a mushy layer during solidification of a binary mixture. We consider a particular limit in which the onset of oscillatory convection just precedes the onset of steady overturning convection, at a prescribed aspect ratio of convection patterns. This asymptotic limit allows us to determine nonlinear solutions analytically. The results provide a complete description of the stability of and transitions between steady and oscillatory convection as functions of the Rayleigh number and the compositional ratio. Of particular focus are the effects of the basic-state asymmetries and non-uniformity in the permeability of the mushy layer, which give rise to abrupt (hysteretic) transitions in the system. We find that the transition between travelling and standing waves, as well as that between standing waves and steady convection, can be hysteretic. The relevance of our theoretical predictions to recent experiments on directionally solidifying mushy layers is also discussed.


2010 ◽  
Vol 140 (5) ◽  
pp. 1011-1039 ◽  
Author(s):  
Hiroaki Kikuchi

AbstractWe study the orbital stability of standing waves for the Klein–Gordon–Schrödinger system in two spatial dimensions. It is proved that the standing wave is stable if the frequency is sufficiently small. To prove this, we obtain the uniqueness of ground state and investigate the spectrum of the appropriate linearized operator by using the perturbation method developed by Genoud and Stuart and Lin and Wei. Then we apply to our system the general theory of Grillakis, Shatah and Strauss.


2012 ◽  
Author(s):  
C. R. P. Courtney ◽  
C. -K. Ong ◽  
B. W. Drinkwater ◽  
P. D. Wilcox ◽  
A. Grinenko

1996 ◽  
Vol 322 ◽  
pp. 1-19 ◽  
Author(s):  
M. Ioualalen ◽  
A. J. Roberts ◽  
C. Kharif

A numerical study of the superharmonic instabilities of short-crested waves on water of finite depth is performed in order to measure their time scales. It is shown that these superharmonic instabilities can be significant-unlike the deep-water case-in parts of the parameter regime. New resonances associated with the standing wave limit are studied closely. These instabilities ‘contaminate’ most of the parameter space, excluding that near two-dimensional progressive waves; however, they are significant only near the standing wave limit. The main result is that very narrow bands of both short-crested waves ‘close’ to two-dimensional standing waves, and of well developed short-crested waves, perturbed by superharmonic instabilities, are unstable for depths shallower than approximately a non-dimensional depth d= 1; the study is performed down to depth d= 0.5 beyond which the computations do not converge sufficiently. As a corollary, the present study predicts that these very narrow sub-domains of short-crested wave fields will not be observable, although most of the short-crested wave fields will be.


Author(s):  
Kripa K. Varanasi ◽  
Samir A. Nayfeh

The damping of flexural vibration by introduction of a layer of low-density foam or powder into a structure is investigated. First, we report on experiments in which a layer of foam attached to an aluminum beam gives rise to significant damping at frequencies high enough to induce standing waves in the foam layer. Next, we provide a simple model for such vibration in which the foam is treated as a two-dimensional elastic continuum in which waves can propagate and find that the model is in good agreement with the experiments. Then the results of experiments in which aluminum beams are filled with a low-density powder are presented. The powder-filled beams exhibit behavior qualitatively like that of the foam-filled beams, but we find that the powder can be adequately modeled as an inviscid compressible fluid.


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