Parametric instability in a fluid with temperature-dependent surface tensionK. Kumar1, A. Bandyopadhyay2 and G. C. Mondal2
1 Department of Physics and Meteorology, Indian Institute of Technology Kharagpur 721 302, India
2 Physics and Applied Mathematics Unit, Indian Statistical Institute 203 Barrackpore Trunk Road, Kolkata 700 108, India
(Received 19 May 2003; accepted in final form 12 November 2003)
Stability of the free surface of a viscous fluid with temperature-dependent surface tension, vibrated sinusoidally in the vertical direction, is presented. The onset of surface waves in a thick layer of fluid is delayed by the inhomogeneity in the surface tension. The latter pushes the marginal stability curves corresponding to harmonic waves upward in the forcing amplitude-wave-number plane more than those corresponding to subharmonic waves in thin layers of low Prandtl number fluids. This leads to an interesting possibility of a multicritical point at the instability onset that may involve only subharmonic waves of different wave numbers.
47.20.Gv - Viscous instability.
47.17.+e - Mechanical properties of fluids.
47.35.+i - Hydrodynamic waves.
© EDP Sciences 2004