Turbulent flow of viscoelastic liquids through an axisymmetric sudden expansion

Abstract An experimental investigation is reported of turbulent flow of three concentrations (0.02, 0.05 and 0.1 wt.%) of an aqueous solution of a polyacrylamide (PAA) through an axisymmetric sudden expansion of area-expansion ratio 4. PAA is a viscoelastic, shear-thinning liquid and two water flows are reported for comparative purposes. For water and the two lowest PAA concentrations, the flow was axisymmetric and large increases in the reattachment length (approximately double the water values) found for these PAA flows. At the highest concentration, 0.1% PAA, the flow was strongly asymmetric and the reattachment length up to three times the value for water.

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