Virginia Polytechnic Institute and State University

Abstract:

The two-layer flow of superposed Giesekus liquids is examined. In order to emphasize the effect of a jump in the second normal stress difference, the analysis is focused on flows where the shear rate, shear stress and first normal stress difference are continuous across the interface. A difference in the second normal stress difference is then the determining factor for interfacial insatiability, with the dominant growth rates being realized purely spanwise modes. The eigenvalue problem for such modes can in principle be solved analytically, although in practice it is feasible to carry out the algebra. We discuss a number of analytical results for more specialized cases as well as numerical computations.