Scopul nostru este sprijinirea şi promovarea cercetării ştiinţifice şi facilitarea comunicării între cercetătorii români din întreaga lume.
Autori: Teodor Burghelea, Enrico Segre, Israel Bar-Joseph, Alex Groisman, Victor Steinberg
Editorial: American Physical Society, Physical Review E, 69, p.066305, 2004.
Microscopic flows are almost universally linear, laminar, and stationary because the Reynolds number, Re,
is usually very small. That impedes mixing in microfluidic devices, which sometimes limits their performance.
Here, we show that truly chaotic flow can be generated in a smooth microchannel of a uniform width at
arbitrarily low Re, if a small amount of flexible polymers is added to the working liquid. The chaotic flow
regime is characterized by randomly fluctuating three-dimensional velocity field and significant growth of the
flow resistance. Although the size of the polymer molecules extended in the flow may become comparable to
the microchannel width, the flow behavior is fully compatible with that in a macroscopic channel in the regime
of elastic turbulence. The chaotic flow leads to quite efficient mixing, which is almost diffusion independent.
For macromolecules, mixing time in this microscopic flow can be three to four orders of magnitude shorter
than due to molecular diffusion.
Cuvinte cheie: efficient mixing, elastic turbuulence. Peclet number