An experimental study of the mechanics of turbulent diffusion when uniformly injecting a drag-reducing polymer solution through a wall adjacent to a fully developed pipe flow of water is described. Experimental diffusion data were obtained using very low injection rates in a porous wall pipe test section designed on the basis of a prior theoretical diffusion analysis with uniform injection. The drag-reducing effectiveness of the polymer only in the wall region, discovered previously, is substantiated by detailed concentration profile, velocity profile and wall shear stress data. These data indicate that an increase in the viscous sublayer thickness is accompanied by an increase in the diffusion sublayer thickness for uniform drag-reducing polymer injection. Also, uniform polymer injection at the wall appeared to somewhat inhibit the turbulent diffusion away from the wall. This type of injection provided drag reduction with a much smaller supply of polymer than required to raise the concentration throughout the shear layer to the same drag-reducing level. (Author)

  • Supplemental Notes:
    • Published in Jul of Hydronautics, V5 N2 pp65-72, Apr 71. Supersedes report dated April 70, AD-709455
  • Corporate Authors:

    Advanced Technology Center, Incorporated

    Dallas, TX  United States 
  • Authors:
    • Walters, R R
    • Wells, C S
  • Publication Date: 1970-12-30

Media Info

  • Pagination: 8 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00019402
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: Reprint
  • Contract Numbers: N00014-69C-0214
  • Files: TRIS
  • Created Date: Nov 19 1971 12:00AM