Sustainable Drag Reduction in Turbulent Taylor-Couette Flows by Depositing Sprayable Superhydrophobic Surfaces

Siddarth Srinivasan, Justin A. Kleingartner, Jonathan B. Gilbert, Robert E. Cohen, Andrew J. B. Milne, and Gareth H. McKinley
Phys. Rev. Lett. 114, 014501 – Published 6 January 2015
PDFHTMLExport Citation

Abstract

We demonstrate a reduction in the measured inner wall shear stress in moderately turbulent Taylor-Couette flows by depositing sprayable superhydrophobic microstructures on the inner rotor surface. The magnitude of reduction becomes progressively larger as the Reynolds number increases up to a value of 22% at Re=8.0×104. We show that the mean skin friction coefficient Cf in the presence of the superhydrophobic coating can be fitted to a modified Prandtl–von Kármán–type relationship of the form (Cf/2)1/2=Mln(Re(Cf/2)1/2)+N+(b/Δr)Re(Cf/2)1/2 from which we extract an effective slip length of b19μm. The dimensionless effective slip length b+=b/δν, where δν is the viscous length scale, is the key parameter that governs the drag reduction and is shown to scale as b+Re1/2 in the limit of high Re.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 1 September 2014

DOI:https://doi.org/10.1103/PhysRevLett.114.014501

© 2015 American Physical Society

Authors & Affiliations

Siddarth Srinivasan, Justin A. Kleingartner, Jonathan B. Gilbert, and Robert E. Cohen*

  • Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA

Andrew J. B. Milne and Gareth H. McKinley

  • Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA

  • *recohen@mit.edu
  • gareth@mit.edu

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 114, Iss. 1 — 9 January 2015

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 Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×