THE DAMPING OF TURBULENT FLOW BY LONG-CHAIN MOLECULES,

Abstract

The paper develops the fundamental idea that velocity fluctuations in turbulent flow near a wall are damped by viscous interaction with a grid of long-chain molecules, thus attenuating the Reynolds stresses and thereby reducing drag. Formulas are derived which relate pipe friction factor with Reynolds number, additive concentration, and a length which is characteristic of the particular additive used. The theory accounts for the essential features of experimental data on velocity profile and friction drag obtained by Elata, Lehrer, and Kahanovitz for guar gum and Ernst for carboxymethylcellulose. The analysis also admits turbulence reduction not only by macromolecules in solution, but also by foreign matter in mixture so long as they move with, or are entrained by, the fluid. (Author)

Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1967
Accession Number
AD0660883

Entities

People

  • E. R. Van Driest

Tags

DTIC Thesaurus Topics

  • Additives (Chemicals)
  • Carboxymethylcellulose
  • Drag
  • Experimental Data
  • Flow
  • Fluid Dynamics
  • Fluid Flow
  • Friction
  • Macromolecules
  • Mechanical Properties
  • Mechanics
  • Molecules
  • Polymers
  • Reynolds Number
  • Stresses
  • Turbulent Flow

Fields of Study

  • Physics

Readers

  • Fluid Dynamics.
  • Fluid Mechanics and Fluid Dynamics.
  • Polymer Science and Technology