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Flow of viscoelastic fluids past a flat plate

1967; Wiley; Volume: 13; Issue: 2 Linguagem: Inglês

10.1002/aic.690130214

1547-5905

R. A. Hermes, A. G. Fredrickson,

Fluid Dynamics and Turbulent Flows

Abstract The flow of viscoelastic fluids past a flat plate has been investigated. Experimental studies were performed with aqueous solutions of sodium carboxymethylcellulose used as viscoelastic fluids and corn syrup as a viscous Newtonian fluid. It was observed that the flow patterns of elastic and inelastic fluids are markedly different. Tracer particles placed in the approaching viscoelastic fluids to follow their motion were seen to first decelerate and then to accelerate until a nearly constant velocity was reached. On the other hand tracer particles in the Newtonian fluid were observed merely to decelerate smoothly to the constant velocity. The drag force measured for the viscoelastic fluids was found to be roughly twice that predicted by inelastic models of fluid behavior. Predicted and measured values of the drag force for the Newtonian fluid agreed well. A discussion of mathematical solutions to the problem of flow of viscoelastic fluids past a flat plate is given. Solutions are obtained for a prototype of flow past a flat plate, the suddenly accelerated flat plate (Stokes' problem) with linear viscoelastic models used. The results from Stokes' problem qualitatively explain the anomalous kinematical behavior and the large drag force.