The Kelvin-Helmholtz instability of a Newtonian viscous fluid overlying a viscoelastic fluid in a porous medium is considered separately for Walters B' and Rivlin-Ericksen viscoelastic fluids. It is found that for the special case when perturbations in the directions of streaming are ignored, the system is unstable for a potentially unstable configuration and the system is stable for a potentially stable configuration for Rivlin-Ericksen viscoelastic fluids, which is in contrast to the case of the Walters B' viscoelastic fluid, where the system can be stable or unstable depending upon kinematic viscoelasticity, medium porosity, relative density of the viscoelastic fluid and medium permeability, for both potentially unstable and potentially stable configurations. In every other direction, a minimum value of wave-number has been found. The system is unstable for all wave-numbers greater than this minimum wave number.
2
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The Kelvin-Helmholtz instability of the plane interface separating two superposed viscous electrically conducting streaming Oldroydian fluids permeated with surface tension and magnetic field in a porous medium is considered. The stability motion is also assumed to have uniform two dimensional streaming velocity. The stability analysis has been carried out for two highly viscous fluids. By applying the normal mode technique to the linearized perturbation equations, the dispersion relation has been derived. As in the case of superposed Newtonian fluids, the system is stable in the potentially stable case and unstable in the potentially unstable case, that holds also for the present case. The behavior of growth rate with respect to kinematic viscosity, elasticity, permeability of porous medium, surface tension and streaming velocity are examined numerically and discussed in detail in section 5.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.