Steady Flow of an Oldroyd 4-Constant Fluid in a Corner Region Formed by Two Planes

Authors: SERDAR BARIŞ

Abstract: The analysis of the flow of a viscoelastic fluid near a corner point finds its application in the design of extrusion dies of technological importance. This paper discusses a problem of this type corresponding to the steady flow of a viscoelastic fluid simulated by the Oldroyd 4-constant fluid model in a corner region formed by two planes. The aim of this study is to investigate theoretically whether or not fluid elasticity is responsible for the formation of circulating cells near the corner, which has been observed experimentally in various polymer processes. Since such circulating cells are detrimental in equipment for polymer processing, it is important to understand and be able to predict the conditions under which circulating cells appear. Using series expansions proposed by Strauss (1974) for the stream function and stress components, the governing equations of the problem are reduced to ordinary differential equations. These equations have been solved by employing a numerical technique. The effects of the viscoelastic parameters on the flow pattern are carefully delineated. There is, unlike the case of Newtonian fluid, a secondary flow near the corner point.

Keywords: Non-radial flow, Oldroyd 4-constant fluid, Viscoelasticity, Circulating cells.

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