TY - GEN
T1 - Rate of decay of a passive scalar in a micro-mixer and the frequency of the advecting velocity fields
AU - Pacheco, J. Rafael
AU - Chen, Kangping
AU - Pacheco-Vega, Arturo
PY - 2009/12/1
Y1 - 2009/12/1
N2 - 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.
AB - 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.
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U2 - 10.1115/HT2009-88626
DO - 10.1115/HT2009-88626
M3 - Conference contribution
AN - SCOPUS:77952843637
SN - 9780791843581
T3 - Proceedings of the ASME Summer Heat Transfer Conference 2009, HT2009
SP - 527
EP - 535
BT - Proceedings of the ASME Summer Heat Transfer Conference 2009, HT2009
T2 - 2009 ASME Summer Heat Transfer Conference, HT2009
Y2 - 19 July 2009 through 23 July 2009
ER -