Francesca Bernardi (UNC-CH) and Dr. Daniel Harris (UNC-CH), GMA Seminar

Title:  Tailoring Tails in Taylor Dispersion – how boundaries shape chemical deliveries in microfluidics

Abstract: We present the results of a combined computational, theoretical, and experimental investigation of the dispersion of a passive scalar in laminar shear flow through rectangular and elliptical channels.  Our findings could potentially be useful in a number of microfluidic applications, some of which will be discussed.

We show through Monte Carlo simulations, asymptotic analysis, and experiments that the cross-sectional aspect ratio of the channel sets the longitudinal asymmetry of the resulting tracer distribution at long times.  Thin channels (aspect ratio << 1) generate distributions with sharp fronts and tapering tails, whereas thick channels (aspect ratio ~ 1) produce the opposite effect.  In addition, our analysis allows us to define a golden aspect ratio which separates thin from thick channels, the value of which is remarkably similar for both the rectangular ducts and the elliptical pipes.