Visualization of channel flow transition in polymer solutins

Abstract

The evolving process of a turbulent spot and the flow pattern downstream of a trlp wire are visualized in a transitional plane Poiseuille flow. The fluids studied are water and polymer solutions. The polymer solutions (Polyacrylamide aq.) are viscoelastic liquids and exhibit turbulent drag reduction. The visualized results show that the polymer solutins have the lower critical Reynolds number to two-dimensional disturbances but are more stable to three-dimensional disturbances relative to Newtonian fluids.