In this study, through using three-layer channels and polymer solution, it is aimed to evaluate the influence that the flow condition (flow rate, shape of channel and solution property) in the channel exerts on the liquid film surface appearance immediately after the discharge, and to clarify the rule factor in which it influences the liquid film surface appearance. Experiments were conducted by taking pictures of the bead surface appearance immediately after the discharge with a high-speed camera by using three-layer channels where the change in the merging point shape was possible. As a result of the examination, the following results were obtained.
(1) As a result of the observation of surface, it is understood a peculiar surface ruggedness (thickness irregularity) is generated when the viscoelastic fluid is used in the direction of the liquid film discharge different from Melt fracture and Sharkskin. It is thought that this irregular thickness is a peculiar phenomenon to the viscoelastic fluid, because when Newtonian fluid is injected, this irregular thickness is not generated, and it is suppressed because of increased residence time in channel.
(2) The factor separation between layers is done at an irregular thickness to specify the rule factor, therefore it has been understood that the correlation is strong in the first normal stress difference generated in the sub-fluid when merging for the incidence of this irregular thickness. Concretely, it is understood that the thickness irregular incidence increases as the first normal stress difference generated in the sub-fluid when merging grows. Moreover, the influence of the main-fluid on the incidence of an irregular thickness in this system is understood to be negligible.

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