Acoustic force model for the fluid flow under standing waves

Lei, Hong; Henry, Daniel; Benhadid, H.

doi:10.1016/j.apacoust.2011.04.007

Cited by 7 publications

(6 citation statements)

References 9 publications

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“…(25)] is suppressed close to the wall in comparison to the parallel-plate channel solution [Eq. (19)]. Note that for the nth resonance k n = nπ/w, the unit vector e 1 in Eq.…”

Section: F Streaming In a Rectangular Channelmentioning

confidence: 99%

“…Also, in most theoretical work either the radiation force or the streaming effects have been studied separately, but not combined with wall effects to obtain a complete description of microparticle * bruus@fysik.dtu.dk acoustophoresis. Recently, a number of numerical studies of acoustic streaming [19][20][21] and acoustophoresis [22,23] have appeared in the literature. In this work, we present a theoretical analysis of acoustic streaming, taking the effect of the vertical sidewalls into account, and apply it to a theoretical study of microparticle acoustophoresis in rectangular microchannels.…”

Section: Introductionmentioning

confidence: 99%

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Ultrasound-induced acoustophoretic motion of microparticles in three dimensions

et al. 2013

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We derive analytical expressions for the three-dimensional (3D) acoustophoretic motion of spherical microparticles in rectangular microchannels. The motion is generated by the acoustic radiation force and the acoustic streaming-induced drag force. In contrast to the classical theory of Rayleigh streaming in shallow, infinite, parallel-plate channels, our theory does include the effect of the microchannel side walls. The resulting predictions agree well with numerics and experimental measurements of the acoustophoretic motion of polystyrene spheres with nominal diameters of 0.537 µm and 5.33 µm. The 3D particle motion was recorded using astigmatism particle tracking velocimetry under controlled thermal and acoustic conditions in a long, straight, rectangular microchannel actuated in one of its transverse standing ultrasound-wave resonance modes with one or two half-wavelengths. The acoustic energy density is calibrated in situ based on measurements of the radiation dominated motion of large 5-µm-diam particles, allowing for quantitative comparison between theoretical predictions and measurements of the streaming induced motion of small 0.5-µm-diam particles.

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“…(25)] is suppressed close to the wall in comparison to the parallel-plate channel solution [Eq. (19)]. Note that for the nth resonance k n = nπ/w, the unit vector e 1 in Eq.…”

Section: F Streaming In a Rectangular Channelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultrasound-induced acoustophoretic motion of microparticles in three dimensions

et al. 2013

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“…1, is valid in the limit of thin boundary layers in medium-sized channels, d % h % l, and a later extension 13 is valid in the limit of thin boundary layers in shallow channels, d . h % l. Moreover, in contrast to rectangular channel cross sections of experimental relevance, the classical analysis of the parallel-plate channel and recent numerical studies of it 21 do not include the effects of the vertical side walls. One exception is the special case of gases in shallow, low-aspect-ratio channels studied by Aktas and Farouk.…”

Section: Introductionmentioning

confidence: 99%

A numerical study of microparticle acoustophoresis driven by acoustic radiation forces and streaming-induced drag forces

Müller

Barnkob

Jensen³

et al. 2012

Lab Chip

511

509

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“…[22][23][24][25] Inside the tube, in the region above the piezoelectric transducer, a characteristic streaming flow pattern containing four horizontal flow rolls is established. 24 This pattern cannot be explained in numerical modeling 20,26 in terms of boundary-driven streaming or classical bulk Eckart streaming, but here we argue, based on our thermoacoustic simulation results, that thermal effects are responsible for this streaming pattern. This result is important as the streaming pattern is used to lead nanoparticles into the central region, where they are trapped by larger seed particles.…”

Section: A Example I: 2d Streaming In a Square Channelmentioning

confidence: 61%

Theory of pressure acoustics with thermoviscous boundary layers and streaming in elastic cavities

Joergensen,

Bruus

2020

Preprint

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We present an effective thermoviscous theory of acoustofluidics including pressure acoustics, thermoviscous boundary layers, and streaming for fluids embedded in elastic cavities. By including thermal fields, we thus extend the effective viscous theory by Bach and Bruus, J. Acoust. Soc. Am. 144, 766 (2018). 1 The acoustic temperature field and the thermoviscous boundary layers are incorporated analytically as effective boundary conditions and timeaveraged body forces on the thermoacoustic bulk fields. Because it avoids resolving the thin boundary layers, the effective model allows for numerical simulation of both thermoviscous acoustic and time-averaged fields in 3D models of acoustofluidic systems. We show how the acoustic streaming depends strongly on steady and oscillating thermal fields through the temperature dependency of the material parameters, in particular the viscosity and the compressibility, affecting both the boundary conditions and spawning additional body forces in the bulk. We also show how even small steady temperature gradients (∼ 1 K/mm) induce gradients in compressibility and density that may result in very high streaming velocities (∼ 1 mm/s) for moderate acoustic energy densities (∼ 100 J/m 3 ).

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Acoustic force model for the fluid flow under standing waves

Cited by 7 publications

References 9 publications

Ultrasound-induced acoustophoretic motion of microparticles in three dimensions

Ultrasound-induced acoustophoretic motion of microparticles in three dimensions

A numerical study of microparticle acoustophoresis driven by acoustic radiation forces and streaming-induced drag forces

Theory of pressure acoustics with thermoviscous boundary layers and streaming in elastic cavities

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