2026-09-19T17:47:50Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/89089 2023-07-11 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Hilgenfeldt, Sascha Thameem, Raqeeb Muddassir 2016-03-02T19:45:11Z 2016-03-02T19:45:11Z 2015-12-11 2015-12 This work seeks to characterize and model the size-dependent behaviour of microparticles in a bubble streaming flow. We show that in microchannels, the steady streaming flow generated by an ultrasonically driven semicylindrical microbubble can be combined with a Poiseuille flow to achieve tunable, high throughput, size-sensitive sorting and trapping of particles much smaller than the bubble itself. We propose a simple geometric mechanism, based on flow speeds and channel geometry, that reliably predicts the sorting behaviour seen in experiment. It is also shown that an asymptotic theory that incorporates the device geometry and superimposed channel flow accurately models key flow features such as peak speeds and particle trajectories. Finally, the forces acting on particles on oscillatory time scales are determined experimentally using a novel method in which the trajectories of small and large particles are compared. These forces are found to scale quadratically with both oscillatory flow speed and particle size. Simulations of particle trajectories are used to show that Saffman lift is not primarily responsible for these forces. Instead, a lubrication theory is proposed that is able to predict both the magnitude and dependence of forces on particles. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2016-03-02 without embargo terms The student, Raqeeb Thameem, accepted the attached license on 2015-12-09 at 21:23. The student, Raqeeb Thameem, submitted this Thesis for approval on 2015-12-09 at 21:39. This Thesis was approved for publication on 2015-12-11 at 13:49. DSpace SAF Submission Ingestion Package generated from Vireo submission #8995 on 2016-03-02 at 12:53:07 Made available in DSpace on 2016-03-02T19:45:11Z (GMT). No. of bitstreams: 2 THAMEEM-THESIS-2015.pdf: 4078005 bytes, checksum: 1736148c2f2efb4f9e9df088332d6398 (MD5) LICENSE.txt: 4211 bytes, checksum: 7dd6f63a692a77067bbe557df70e42fe (MD5) Previous issue date: 2015-12-11 application/pdf http://hdl.handle.net/2142/89089 en Copyright 2015 Raqeeb Muddassir Thameem Microfluidics Acoustics Streaming Hydrodynamics Experimental fluid mechanics Microbubbles Sorting Oscillatory flow Quantifying particle sorting in microbubble streaming flows text text Mechanical Science & Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Thesis M.S.