Aspect ratio dependence of
charge transport in turbulent electroconvection
Aspect ratio dependence of
charge transport in
turbulent electroconvection
Physical Review Letters, 92, 084503 (2004).
Peichun Tsai (1), Zahir A. Daya (2) and Stephen W.
Morris (1)
(1) Department of Physics,
University of Toronto, 60 St. George St., Toronto, Ontario, Canada M5S 1A7.
(2) Center for Nonlinear Studies and Condensed Matter & Thermal
Physics Group, MS-B258,
Los Alamos National Laboratory, Los Alamos, NM 87545
We present measurements of the normalized charge transport or Nusselt
number Nu as a function of the aspect ratio Gamma for
turbulent convection in an electrically driven film. In analogy with
turbulent Rayleigh-Bénard convection, we develop the relevant
theoretical framework in which we discuss the local-power-law-scaling of Nu with a dimensionless electrical forcing parameter R. For these
experiments where 10^4 < R < 2 X 10^5 we
find that Nu ~ F(Gamma)R ^ gamma with gamma either 0.26 +/- 0.02 or 0.20 +/- 0.03, in excellent agreement with the theoretical predictions of gamma = 1/4 and 1/5. Our measurements of the aspect ratio-dependence of
Nu for 0.3 < Gamma < 17 compares favorably with the
function F(Gamma) from the scaling theory.
