(224f) Electrokinetically Driven Micro-Turbulence in Microfluidics with Re in the Order of 1

We report an electrokinetically driven micro-turbulent flow phenomenon in a microchannel, where the Reynolds number (Re) based on bulk flow and channel width is in the order of 10. As we know the critical Re in a channel flow is about 2000 and a pressure driven flow with Re in the order of 10 is definitely laminar, hence, the fluid mixing is very flow. Although there have been electrokinetical micromixers published that can increase mixing, the flows are believed not to be turbulence, but chaotic. Here we design a novel electrokinetically forced pressure driven flow with Re in the order of 10 to achieve turbulence like flow. To confirm that the flow is turbulence, Laser Induced Fluorescence Photobleaching Anemometer (LIFPA) is used to measure the corresponding flow velocity features. LIFPA enables ultrahigh temporal and spatial resolution measurement. We report the measured flow features: high dissipation and diffusion rate, multiscale continuous power spectra and 3-D flow. The results open a new view of turbulence at microscale.