Abstract
A study is carried out for viscoelasitic fluids in two dimensional two-cycle diverging-converging channels. In order to investigate flow behavior in the channels, experiments are conducted using polyacrylamide water solutions as model viscoelastic fluids with which measurements of pressure and velocity are made together with observation by flow visualization. In visualization results, various modes of complicated flow patterns, which are caused by viscoelastic effect are observed, and the classification of prevailing flow modes is obtained. By measurements of pressure along channel walls, it is found that additional pressure losses exist related with an appearance of the extra normal stress due to the viscoelasticity. Furthermore, by measurements of velocity in the center line of the channels, the symmetry breaking flow deflection is found to occur at the critical Reynolds number.
