Anomalous Flow of Viscoelastic Fluid from Circular Nozzles : Case of repeating wavy smooth and melt fracture

Abstract

This paper deals with anomalous shapes of viscoelastic fluid extruded from circular nozzles. The working fluid employed was prepared by mixing nine kinds of low-density polyethylene sold by several makers. The extrudate picked up consists of two distinct regions, wavy smooth and melt fracture, which are arrayed alternately. Their period and ratio were studied. The data were rather scattered but mean values were arranged well. It was elucidated that the frequency of the period was in direct proportion to the shear rate, and the ratio gradually approached the fixed value with increasing shear rate.