TY - JOUR
T1 - Opposing shear-induced forces dominate inertial focusing in curved channels and high Reynolds numbers
AU - Keinan, Eliezer
AU - Ezra, Elishai
AU - Nahmias, Yaakov
N1 - Publisher Copyright:
© 2015 AIP Publishing LLC.
PY - 2015/11/9
Y1 - 2015/11/9
N2 - Inertial focusing is the migration of particles in fluid toward equilibrium, where current theory predicts that shear-induced and wall-induced lift forces are balanced. First reported in 1961, this Segre-Silberberg effect is particularly useful for microfluidic isolation of cells and particles. Interestingly, recent work demonstrated particle focusing at high Reynolds numbers that cannot be explained by current theory. In this work, we show that non-monotonous velocity profiles, such as those developed in curved channels, create peripheral velocity maxima in which opposing shear-induced forces dominate over wall effects. Similarly, entry effects amplified in high Reynolds flow produce an equivalent trapping mechanism in short, straight channels. This focusing mechanism in the developing flow regime enables a 10-fold miniaturization of inertial focusing devices, while our model corrects long-standing misconceptions about the nature of mechanical forces governing inertial focusing in curved channels.
AB - Inertial focusing is the migration of particles in fluid toward equilibrium, where current theory predicts that shear-induced and wall-induced lift forces are balanced. First reported in 1961, this Segre-Silberberg effect is particularly useful for microfluidic isolation of cells and particles. Interestingly, recent work demonstrated particle focusing at high Reynolds numbers that cannot be explained by current theory. In this work, we show that non-monotonous velocity profiles, such as those developed in curved channels, create peripheral velocity maxima in which opposing shear-induced forces dominate over wall effects. Similarly, entry effects amplified in high Reynolds flow produce an equivalent trapping mechanism in short, straight channels. This focusing mechanism in the developing flow regime enables a 10-fold miniaturization of inertial focusing devices, while our model corrects long-standing misconceptions about the nature of mechanical forces governing inertial focusing in curved channels.
UR - http://www.scopus.com/inward/record.url?scp=84947474592&partnerID=8YFLogxK
U2 - 10.1063/1.4935466
DO - 10.1063/1.4935466
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AN - SCOPUS:84947474592
SN - 0003-6951
VL - 107
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 19
M1 - 193507
ER -