Abstract
Behavior of a shear layer in a narrow closed channel was observed under periodic excitations. The cross-section of the channel was 15 x 15mm, the characteristic velocity was 12cm/sec, and the thickness of the shear layer wasO (2mm), so that the effects of the side walls were not negligible. Excitation was given at an upstream position on one side of the splitter plate by changing the flow rate periodically with frequency 6-40Hz. Motion of the shear layer depended on the frequency and the amplitude of the excitation. In most cases the layer became wavy and showed a roll-up motion, as has been observed in past studies. But, for a strong excitation with frequency 40 Hz, the layer showed a certain kind of chaotic behavior, in which the layer shifted up and down slowly or tilted irregularly in the spanwise direction. Mechanism of this phenomenon is not clear, but it seems to suggest a new type of chaos in hydrodynamics.
