The time-dependent thermocapillary and buoyancy convection was simulated in liquid bridges of different geometries: straight, concave, convex ( and for a wide range of Re and Gr numbers). For liquid bridges with a flat interface, the instability corresponding to an azimuthal wavenumber of is not found. Under gravity conditions, the axially running waves (azimuthal wave number ), are only predicted for deformable liquid bridge for Reynolds number The flow pattern is characterized by a large toroidal vortex with motion on the free surface from the hot disk towards the cold one and a smaller secondary vortex with an opposite direction of circulation which forms due to the buoyancy forces. It is shown that the main reason for the instability is the existence of a cold finger near the hot disk. The time dependence is characterized by small accelerations and decelerations of the primary convective cell which are caused by minute variations of the surface temperature profile. The transition from the stable to oscillatory flow is related to a Hopf bifurcation. The supercritical type of Hopf bifurcation is verified by the negative sign of Landau constant λ for the entire range of volumes.
Stability of liquid bridges with non-flat free surface
Space technology and applications international forum -1999 ; 1999 ; Albuquerque, New Mexico (USA)
AIP Conference Proceedings ; 458 , 1 ; 824-829
22.01.1999
6 pages
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
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