Experimental study on drag-reducing channel flow with surfactant additives-Spatial structure of turbulence investigated by PIV system

Yasuo Kawaguchi, Takehiko Segawa, Ziping Feng, Peiwen Li

Research output: Contribution to journalArticle

100 Scopus citations

Abstract

The turbulent frictional drag of water can be reduced dramatically by adding small amounts of drag-reducing materials, such as polymers or surfactants. As a percentage drag reduction of 80% can easily be achieved, this technique is thought to be the most practical method of reducing turbulent frictional drag. In this work, a double pulse particle image velocimetry (PIV) system was used to clarify the spatial velocity distribution of surfactant solution flow in a two-dimensional channel. A type of cationic surfactant cetyltrimethyl ammonium chloride (C16H33N(CH3)3Cl) mixed with the same weight of counter-ion material NaSal (HOC6H4COONa) was used as a drag-reducing additive to water at a mass concentration of 40 ppm. Instantaneous velocity distribution taken by PIV was examined to clarify the effect of surfactant. It was found that the instantaneous velocity distribution taken in water flow exhibits penetration from the low-speed fluid region into the high-speed region, which is one of the important events of turbulence energy production and turbulent mixing. Although this structure is commonly observed in water flow, it was not found in drag-reducing flow under the same Reynolds number. The strong vorticity fluctuation near the wall also disappeared and the integral length scale in streamwise direction of turbulent fluctuation had a smaller value in surfactant solution flow.

Original languageEnglish (US)
Pages (from-to)700-709
Number of pages10
JournalInternational Journal of Heat and Fluid Flow
Volume23
Issue number5
DOIs
StatePublished - Oct 1 2002
Externally publishedYes

Keywords

  • Channel flow
  • Drag reduction
  • PIV
  • Spatial structure
  • Surfactant
  • Turbulence

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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