Journal ArticleDOI
Role of shear induced diffusion in acoustophoretic focusing of dense suspensions
S. Karthick,Ashis Kumar Sen +1 more
TLDR
In this paper, the authors investigate the interplay between acoustic and shear induced diffusion (SID) forces in acoustophoretic focusing of dense suspensions in a microchannel and present a theoretical model which accurately predicts the width of the focused band in terms of shear rate, acoustic energy density, and particle concentration.Abstract:
We investigate the interplay between acoustic and shear induced diffusion (SID) forces in acoustophoretic focusing of dense suspensions in a microchannel. A theoretical model is presented which accurately predicts the width of the focused band in terms of shear rate, acoustic energy density, and particle concentration. The role of SID is clearly demonstrated by switching off the acoustic field, which leads to the instantaneous spreading of the focused band. At a given acoustic energy density and particle concentration, there exists a critical shear rate Γcr above which the focusing of microparticles is prevented. For Γ<Γcr, an equilibrium focused band is formed whose width remains constant downstream.read more
Citations
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Journal ArticleDOI
Label-free microfluidic sorting of microparticles.
TL;DR: An updated overview of the state of the art for passive label-free microparticle separation, with emphasis on performance and operational conditions is provided and the newly emerging approach based on shear-induced diffusion is highlighted.
Journal ArticleDOI
Improved Understanding of Acoustophoresis and Development of an Acoustofluidic Device for Blood Plasma Separation
S. Karthick,Ashis Kumar Sen +1 more
TL;DR: In this paper, the physics behind the separation of plasma from whole blood using acoustophoresis (movement driven by sound waves) is not well understood, and experiments and simulations are used to provide an improved understanding.
Journal ArticleDOI
Aggregation of a dense suspension of particles in a microwell using surface acoustic wave microcentrifugation
TL;DR: In this article, the authors investigated the aggregation of a dense suspension of particles (volume fraction, = 0.1 ) in a PDMS microwell by employing surface acoustic wave (SAW) microcentrifugation.
Journal ArticleDOI
Cross-stream migration and coalescence of droplets in a microchannel co-flow using magnetophoresis
TL;DR: In this article, the authors studied the mechanism of cross-stream migration and the coalescence of aqueous droplets flowing in an oil-based ferrofluid with a co-flowing aouous stream in the presence of a magnetic field and revealed that the migration phenomenon is governed by the advection and magnetophoretic (τm) time scales.
Journal ArticleDOI
Continuous Droplet Coalescence in a Microchannel Coflow Using Bulk Acoustic Waves
TL;DR: In this article, the authors studied the physics of acoustics-driven coalescence of liquid droplets with a liquid stream and found that the phenomenon is also governed by the acoustic capillary number and relative widths of the coflowing oil and aqueous streams.
References
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Journal ArticleDOI
The shear-induced migration of particles in concentrated suspensions
TL;DR: In this article, it was shown that shear-induced migration of particles out of the sheared Couette gap and into the fluid reservoir, which reduces the particle concentration in the gap and thereby the observed viscosity, is consistent with a gap-limited shearinduced diffusion process normal to the plane of shear, with the relevant diffusion coefficient being proportional to the applied shear rate.
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A constitutive equation for concentrated suspensions that accounts for shear‐induced particle migration
TL;DR: In this article, a constitutive equation for computing particle concentration and velocity fields in concentrated monomodal suspensions is proposed that consists of two parts: a Newtonian constitutive equations in which the viscosity depends on the local particle volume fraction and a diffusion equation that accounts for shear-induced particle migration.
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Acoustofluidics 7: The acoustic radiation force on small particles
TL;DR: The theory of the acoustic radiation force is presented; a second-order, time-averaged effect responsible for the acoustophoretic motion of suspended, micrometre-sized particles in an ultrasound field.
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The rheological behavior of concentrated colloidal dispersions
TL;DR: In this article, a simple model for the rheological behavior of concentrated colloidal dispersions is developed for a suspension of Brownian hard spheres, where two contributions to the macroscopic stress: a hydrodynamic and a Brownian stress.