INERTIAL EFFECTS AND LONG WAVES IN MULTILAYER PLANE POISEUILLE FLOWS

The objective of this work is to clarify the role of inertial effects on the long-wavelength instabilities and dynamics of multilayer plane Poiseuille flows. A weakly nonlinear set of equations governing the ev olution of interfacial waves is derived and examined. Numerical simula tions show that for the flows irregular interface profiles are generic . For some systems a curious behaviour of interfaces is revealed: depe nding on initial conditions, interfaces evolve into irregular or solit on-like structures.