Stability of hydrothermal-wave states

The half-zone model is investigated for unit aspect ratio, zero gravity, an d Prandtl numbers Pr = 1.5...7 by numerical simulations. For thermocapillar y Reynolds numbers Re > Re-c, the 2D stationary flow is unstable to 3D trav elling waves. In the simulations, standing waves can be generated slightly above Re,. It is found, that these states are unstable and decay into eithe r a clock or a counter-clockwise propagating wave. Amplitude equations are used to quantitatively describe the instability of the standing wave states and to estimate the range of Pr within which only travelling waves are sta ble.