Former collaborators: T. Besson, B. Pier, S. Edwards
Many different types of ordered and disordered standing wave patterns are formed at the surface of a vertically oscillating layer of fluid. We have been investigating both the ordered patterns formed near the onset of the surface wave instability, and the disordered patterns formed at somewhat higher excitation amplitude. The phenomena depend on the viscosity of the fluid, the excitation frequency, and the excitation amplitude. Examples of hexagonal, square, and striped patterns are shown below (at viscosity about 50 times that of water). The container is 32 cm in diameter, and the silicone oil is 3 mm deep. The unusually large diameter and high attainable acceleration reveal novel phenomena.
Grey scale images are obtained using a CCD camera and a frame grabber. The coloring is artificial to enhance the images. Lighter shades correspond to large amplitudes and darker shades to small amplitudes.
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