The linear stability of superposed inviscid and viscous stagnation-point flows

We investigate the stability of two-layer stagnation-point and rotating flows with differing densities and viscosities when the interface between the layers is flat. We investigate the stability of an inviscid two-layer rotating flow as an initial-value problem and find instability. Then, building on the work of Brattkus & Davis (1991), who examined the stability of stagnation-point flow over a boundary, the linear stability of a two-layer viscous stagnation-point flow with a similarity-solution basic state is examined under the long-wave approximation and solved numerically. Properties of the system and limiting cases of the flow configuration are also discussed.