A novel method using ultrasound is introduced for frost suppression on cold flat surface.The dynamic behavior of water droplets dropped on aluminum surface subjected to 20 kHz and 50W ultrasonic vibration was visually studied.The transient processes of deformation

spreading and atomization of water droplets on aluminum surface due to ultrasonic vibration were recorded.The experimental results indicate that the intense disturbance first occurs in the water droplet subjected to instantaneous incentive due to the effect of ultrasonic vibration and then the droplet deforms and spreads.When the liquid film thickness decreases to a critical value

the water droplet instantaneously atomizes.The interfacial shear force generated by ultrasonic mechanical effect and the high pressure impact induced by ultrasonic cavitation might be respectively the dominant factor for droplet deformation and atomization.The results preliminarily show that the ultrasonic vibration can instantaneously atomize the water droplet on aluminum surface in the initial stage of frosting

which provides a possibility for effective frost suppression on cold surface.