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Direct measurements of viscoelastic flows in micro-contractions
ASME Third International Conference on Microchannels and Minichannels
  • Shelly Gulati, University of California, Berkeley
  • Susan J. Muller, University of California, Berkeley
  • Dorian Liepmann, University of California, Berkeley
Document Type
Conference Presentation
Toronto, Ontario, Canada
Conference Dates
June 13-15, 2005
Date of Presentation
Direct measurement techniques are employed to quantify the kinematics of DNA flows in micro-contraction devices. Flow through micro-contractions subjects the fluid to large spatial gradients in velocity, thereby eliciting viscoelastic effects. Additionally, in this microfluidic flow environment, the fully extended length of the macromolecule L will approach the characteristic length scale of the channel geometry h. This is a unique flow environment that is not yet well understood. Knowledge of the fundamental physics that govern this flow regime will have a profound impact on optimization of lab-on-a-chip systems incorporating macromolecular flows. This study investigates the flow of semi-dilute λ-DNA solutions in a 2:1 micro-contraction where L/h ∼ 0.32. Video microscopy and streak images of semi-dilute DNA flows reveal large vortex regions in the corners of the contraction, which are indicative of strong elastic behavior. Velocity fields constructed using Digital Particle Image Velocimetry (DPIV) demonstrate the first use of this tool for obtaining velocity measurements of viscoelastic flows in microfluidic systems.
Citation Information
Shelly Gulati, Susan J. Muller and Dorian Liepmann. "Direct measurements of viscoelastic flows in micro-contractions" ASME Third International Conference on Microchannels and Minichannels (2005)
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