THRESHOLD DYNAMICS OF SINGULAR GRAVITY-CAPILLARY WAVES

Surface wave experiments confirm predictions of a threshold amplitude for droplet ejection. Droplet ejection and spray originate from highly focused surface singularities in the simplest states. The threshold i s found to be dependent on forcing frequency and surface tension in ac cordance with a simple scaling theory presented here. Linear stability analysis indicates that the dynamics of the ejections at low frequenc y are low dimensional. Observations confirm this, and show periodic ej ections as the simplest observed state. Ejecting states at higher freq uency appear turbulent in nature.