TY - JOUR
T1 - Mixing-dynamics of a passive scalar in a three-dimensional microchannel
AU - Pacheco, J. Rafael
AU - Pacheco-Vega, Arturo
AU - Chen, Kangping
N1 - Funding Information:
This work was supported by the National Science Foundation through grants CBET-0608850 and HRD-0932421 . We are grateful to Professors S. Wiggins, A. Neishtadt and Ms. S. Stanton for many valuable comments on the manuscript. The authors acknowledge Texas Advanced Computing Center (TACC) at the University of Texas at Austin and Ira A. Fulton High Performance Computing Initiative at Arizona State University, both members of the NSF-funded Teragrid, for providing HPC and visualization resources.
PY - 2011/1/31
Y1 - 2011/1/31
N2 - The mixing of a diffusive passive-scalar driven by electro-osmotic fluid motion in 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 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 time interval considered. An exponential decay of the variance of the concentration, and associated moments, is found to exist for both periodic and random velocity fields. The numerical results also indicate that measures of chaoticity (in a deterministic chaotic system) decay exponentially in the frequency - at large frequencies - in agreement with the theory.
AB - The mixing of a diffusive passive-scalar driven by electro-osmotic fluid motion in 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 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 time interval considered. An exponential decay of the variance of the concentration, and associated moments, is found to exist for both periodic and random velocity fields. The numerical results also indicate that measures of chaoticity (in a deterministic chaotic system) decay exponentially in the frequency - at large frequencies - in agreement with the theory.
KW - Chaotic mixing
KW - Electro-osmotic flow
KW - Low Reynolds number
KW - Random modulation
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U2 - 10.1016/j.ijheatmasstransfer.2010.09.055
DO - 10.1016/j.ijheatmasstransfer.2010.09.055
M3 - Article
AN - SCOPUS:78649918827
SN - 0017-9310
VL - 54
SP - 959
EP - 966
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
IS - 4
ER -