Separation efficiency maximization in acoustofluidic systems: study of the sample launch-position

Abstract

We theoretically and numerically show how to optimize the separation-efficiency of acoustofluidic systems by a non-trivial selection of sample-injection position.

On the methodologies for the assessment of the impact of parameters in acoustophoretic separation devices

“…Furthermore, it must be noticed that in citing Garofalo [3] and by addressing that "the theoretical analysis of particle kinematics in free-flow acoustophoretic devices was already reported", they definitively over-looked the opportunity to discuss the results of their study of dispersion against a seemingly different method for the study of the "cross-sectional dispersion". Indeed, it is noticeable the similarity between the behavior of the bandwidth [1,2] and that of the variance formerly presented in [3] and successively in [5,6]. This affinity goes beyond the bandwidth and the variance when one compares the graphs of the trajectories/bandwidth in [1] and those for the spatial distributions in [3].…”

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In this communication I reconcile the kinematic method illustrated by some authors [1,2] in studying the impact of system and suspension parameters on acoustophoretic separations with the statistical method formerly proposed by Garofalo [3,4] and lately extended to particle populations by the same author [5,6]. The connection between these two methods is established by (i) reinterpreting the kinematic method in terms of tangent space dynamics, and (ii) transforming the dynamics in the tangent space into the dynamics of the area elements.

…”

“…Some authors [1,2] have investigated the influence of the particle and system parameters on the acoustophoretic separation of microparticles by considering the integration of the equation of motion for a particle suspended in a medium dx dt = v(x, p) ,…”

“…Since in [1,2] the authors aimed to develop the analysis for quantifying the separation of biological samples, they suggested, by using the words "dispersed objects", "populations" or "average position", that the statistics of the sample was taken into account to some extent. However, in their paper they did not consider any statistical analysis of dispersion during the dynamics of the separation process.…”

“…This led to a troublesome analysis (see Eqs. (9) in [2]) where the number of equations is quite large. However, the problem of studying the influence of small deviations from initial conditions is well-known in dynamic system theory.…”