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Title:Oscillatory and streaming flows in microchannels
Author(s):Vishwanathan, Giri
Advisor(s):Juarez, Gabriel
Department / Program:Mechanical Sci & Engineering
Discipline:Mechanical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):microfluidics, oscillatory, acoustic streaming, viscoelastic
Abstract:Microfluidics is the study of liquid flow in the small scale (10-1000 micron) channel networks and is widely used in chemistry and biology as a platform for analysis synthesis and manipulation. The construction, performance characterization and validation of an oscillatory driver capable of producing oscillatory flow in microfluidic channels in the frequency range 10-1000 Hz is detailed. The application of micro-scale oscillatory flows is broadly divided into two categories. The first using the time reversing nature of the flow for decreasing device size or for prolonged optical observation and the second involving the the use of steady secondary rectified flows which arise due to fluid inertia. Both of these application categories are shown to be effectively realizable in this frequency range through the demonstration of inertial particle focusing in the former and microscale mixing in the latter. Additionally, the particular case of steady rectified flows originating from a rigid cylindrical boundary or steady streaming as it is commonly known is used to perform a probe-free optical measurement of the kinematic viscosity of Newtonian liquids. This is followed by a study of steady streaming flows in well characterized model viscoelastic liquids of two kinds: namely the Boger fluid and the fractional Maxwell liquid. The streaming flow. Steady streaming velocity profiles in elastic liquids with strong shear thinning (fractional Maxwell liquids), however, display two unique features in the confined microfluidic system: (i) a non monotonic evolution of the inner streaming layer with increasing frequency, first growing then decreasing in width, and (ii) a clear asymmetry in the flow profile at high frequencies.
Issue Date:2019-12-03
Rights Information:Copyright 2019 Giri Vishwanathan
Date Available in IDEALS:2020-03-02
Date Deposited:2019-12

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