Fluid delivery devices and methods are described, where the device may comprise a piezoelectric actuator operatively coupled to an ampoule with fluid, under a preloading force. The ampoule may comprise a thin-walled thermoplastic package which includes one or more apertures positioned on the wall of the ampoule. The piezoelectric actuator may be configured to clamp at least partially around the circumference of the ampoule and apply oscillations to its wall. The oscillations, typically in ultrasonic frequency, produce cycles of acoustic pressure in the fluid, leading to ejection of the fluid droplets or streams from the apertures.