CIFICEN   24414
CENTRO DE INVESTIGACIONES EN FISICA E INGENIERIA DEL CENTRO DE LA PROVINCIA DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Inertial and dimensional effects on the instability of a thin film
Autor/es:
M. SELLIER; J. A. DIEZ; A. G. GONZÁLEZ
Revista:
JOURNAL OF FLUID MECHANICS
Editorial:
CAMBRIDGE UNIV PRESS
Referencias:
Lugar: Cambridge; Año: 2016 vol. 787 p. 449 - 449
ISSN:
0022-1120
Resumen:
We consider here the effects of inertia on the instability of a flat liquid film under the effects of capillary and intermolecular forces (van der Waals interaction). Firstly, we perform the linear stability analysis within the long wave approximation, which shows that the inclusion of inertia does not produce new regions of instability other than the one previously known from the usual lubrication case. The wavelength, $lambda_m$, corresponding to he maximum growth, $omega_m$, and the critical (marginal) wavelength do not change at all. The most affected feature of the instability under an increase of the Laplace number is the noticeable decrease of the growth rates of the unstable modes. In order to put in evidence the effects of the bidimensional aspects of the flow(neglected in the long wave approximation), we also calculate the dispersion relation of the instability from the linearized version of the complete Navier-Stokes (N--S) equation. Unlike the long wave approximation, the bidimensional model shows that $lambda_m$ can vary significantly with inertia when the aspect ratio of the film is not sufficiently small. We also perform numerical simulations of the nonlinear N--S equations and analyze to which extent the linear predictions can be applied depending on both the amount ofinertia involved and the aspect ratio of the film.
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