Figure 2.

(a) Transverse counter-rotating microvortices within the cross section of the curved channel. Dean flow is generated by the inertial mismatch and centrifugation effects in the cross section of microchannel [4]. Adapted with permission from Di Carlo. (b) Optical microscopic images of the dyed fluid flow distribution captured at the end of the spiral micromixer, illustrating the mixing performance at different flow rates. Re is gradually increased from 3 to 30 [38]. Adapted with permission from Howell Jr. et al. (c) Schematic drawing of the three-dimensional focusing of co-flow streams in the planar spiral microchannel with the assistance of Dean vortices [39]. Adapted with permission from Mao et al. (d) Modified Dean flow separation method using the spiral microchannel with trapezoid cross section [40]. Adapted with permission from Wu et al. (e) High throughput blood plasma extraction using multiplexing slanted spiral microchannel with the trapezoidal cross section [27]. Adapted with permission from Rafeie et al. (f) Confined spiral microchannel with ordered micro-obstacles for the accelerated Dean flow particle manipulation [41]. Adapted with permission from Shen et al.