Internal waves excited by the Marangoni effect

Traveling periodic internal wave trains are generated in liquid layers duri ng the absorption process of a miscible surface-active substance out of the vapor phase. In our nonstationary experimental runs, internal waves are ex cited by surface waves, which had been previously generated by a surface-te nsion-gradient-driven instability. The internal wave trains adjust their wa ve number by an Eckhaus instability. Close to the instability threshold nar row and extended pulses are observed. Furthermore, the wave trains can alte r their traveling direction, i.e., one wave train traveling in one directio n yields to another train, in general of different wave number, traveling i n the opposite direction.