Dynamics of secondary instability in Bénard Marangoni convection with unidimensional heating

摘要

The dynamics of Bknard-Marangoni convection with unidimensional heating in a purefluid is studied experimentally. Convection begins with rolls parallel to the heater. Thecharacteristics of these primary rolls have been determined. When the temperature differenceacross the liquid layer is increased beyond a critical value a secondary instability appears.Motions transverse to the heater with a definite wavelength can be seen. Moreover, for smallangles between the heater and the fluid surface, the pattern drifts along the heater with avelocity that depends almost linearly on the inclination. A phenomenological phase equation isproposed to interpret this observation.