Rate of decay of a passive scalar in a micro-mixer and the frequency of the advecting velocity fields

J. Rafael Pacheco, Kangping Chen, Arturo Pacheco-Vega

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In the current work, the mixing of a diffusive passive-scalar, e.g., thermal energy or species concentration, driven by electro-osmotic fluid motion being induced by an applied potential across a micro-channel is studied numerically. Secondary time-dependent periodic or random electric fields, orthogonal to the main stream, are applied to generate cross-sectional mixing. This investigation focuses on the mixing dynamics and its dependence on the frequency (period) of the driving mechanism. For periodic flows, the probability density function (PDF) of the scaled passive scalar (i.e., concentration), settles into a self-similar curve showing spatially repeating patterns. In contrast, for random flows there is a lack of self-similarity in the PDF for the interval of time considered in this investigation. The present study confirms an exponential decay of the variance of the concentration for the periodic and random flows.

Original languageEnglish (US)
Title of host publicationProceedings of the ASME Summer Heat Transfer Conference 2009, HT2009
Pages527-535
Number of pages9
DOIs
StatePublished - Dec 1 2009
Event2009 ASME Summer Heat Transfer Conference, HT2009 - San Francisco, CA, United States
Duration: Jul 19 2009Jul 23 2009

Publication series

NameProceedings of the ASME Summer Heat Transfer Conference 2009, HT2009
Volume3

Other

Other2009 ASME Summer Heat Transfer Conference, HT2009
CountryUnited States
CitySan Francisco, CA
Period7/19/097/23/09

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

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