Mikhail V. Khenner | Searcharxiv

arXiv1999

Longwave Interface Instability In Two-Fluid Vibrational Flow

We consider longwave mode of the interface instability in the system comprising of two immiscible fluid layers. The fluids fill out plane horizontal cavity which is subjected to horizontal harmonic vibration. The analysis is performed within the framework of "high frequency of the vibration" approximation and the averaging procedure. The nonlinear equation (having the form of Newton's second law) for the amplitude of interface deformation is obtained by means of multiple scales method. It is shown that (in addition to previously detected quasistationary periodic solutions) the equation has a class of quasistationary solitary solutions.

patt-sol↗

arXiv1999

Stability of Plane-Parallel Vibrational Flow In a Two-Layer System

The stability of the interface separating two immiscible incompressible fluids of different densities and viscosities is considered in the case of fluids filling a cavity which performs horizontal harmonic oscillation. There exists a simple basic state which corresponds to the unperturbed interface and plane-parallel unsteady counter flows; the properties of this state are examined. A linear stability problem for the interface is formulated and solved a) for both inviscid and b) for both viscous fluids. A transformation is found which reduces the linear stability problem under inviscid approximation to the Mathieu equation. The parametric resonant regions of instability associated with the intensification of capillary-gravity waves at the interface are examined and the results are compared to those found in the viscous case in a fully numerical investigation.

physics.flu-dyn↗