The loss of stability in ground based experiments in liquid bridges

In this study our primary goal is to investigate the loss of stability of the steady convection in deformable liquid bridges. Definitely, the deformation plays an important role in the transition process from the steady axi-symmetric 2-D basic state to the 3-D periodical one. As it was shown experimentally by many researchers, the critical Marangoni number is very sensitive to the volume of liquid.

It seems to be proved^1–4, that the critical wave number for high Prandtl fluids (for example, silicone oil of different viscosities. Pr > 50) is m = 1 for aspect ratios Γ = height/radius ≥ 1.0 regardless of the free surface shape. But the data from our last experiments show, that by changing surrounding conditions around the liquid bridge we can change the critical wave number. Particularly, by placing the liquid bridge of diameter 2r = 6mm into another cylindrical volume of the diameter 2R = 12mm kept at constant temperature, the critical mode is switched from m = 1 to m = 2.