Scaling of velocity and scalar structure functions in ac electrokinetic turbulence

Wei Zhao and Guiren Wang
Phys. Rev. E 95, 023111 – Published 22 February 2017

Abstract

Electrokinetic (EK) turbulence or electrohydrodynamic (EHD) turbulence has been recently achieved in different fluids under both ac [G. Wang et al., Lab Chip 14, 1452 (2014); Phys. Rev. E 93, 013106 (2016)] and dc electric fields [A. Varshney et al., Soft Matter 12, 1759 (2016)]. Here, through dimensional analysis, scaling laws of both velocity and electric conductivity structure functions in the forced cascade region of ac EK turbulence can be predicated (similar to Bolgiano-Obukhov scaling law in turbulent Rayleigh-Bénard convection), in either macroscale or microscale flows. In the forced cascade region, EK force, which relies on the direct cascade of conductivity structures, injects energy directly into a wide spectral region to sustain the flow disturbance. The scaling exponents of the second-order velocity and conductivity structures are 2/5 and 4/5, respectively. In addition to the scaling regions, two characteristic small length scales are derived for both weak and strong electric body forces, respectively. This theoretical investigation can significantly enhance our understanding of EK or EHD turbulence while forced by an ac electric field. It can further broaden our understanding of the forced cascade region of forced turbulence and make the manipulation of the turbulent cascade process more flexible and controllable.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 17 January 2015
  • Revised 2 November 2016

DOI:https://doi.org/10.1103/PhysRevE.95.023111

©2017 American Physical Society

Physics Subject Headings (PhySH)

Fluid Dynamics

Authors & Affiliations

Wei Zhao1,2 and Guiren Wang2,3,*

  • 1Institute of Photonics and Photon-technology, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Northwest University, 229 North Taibai Road, Xi'an 710069, People's Republic of China
  • 2Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA
  • 3College of Biomedical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA

  • *guirenwang@sc.edu

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 95, Iss. 2 — February 2017

Reuse & Permissions
Access Options
CHORUS

Article Available via CHORUS

Download Accepted Manuscript
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review E

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×