Transition to parametric wave patterns in a vertically oscillated granular layer

摘要: Experiments on vertically oscillated granular layers reveal, at a critical acceleration, well-defined transition from flat surface to standing wave patterns oscillating half the excitation frequency. The observed in cylindrical container are squares or stripes; continuous between these states occurs when vibration frequency is varied constant acceleration. dispersion relation for parametric waves similar that gravity fluid, but exhibits cutoff associated with particle size.