Experiments on ring wave packet generated by water drop

The propagation of ring wave packet （composed of carrier waves modulated by an envelope） generated by a water drop was studied experimentally. It is a localized wave packet propagating with constant velocity and low diffusion. The wavelength, the amplitude and the waveform of the carrier waves, the velocity of the carrier waves and the packet have been measured. The measured wavelength λa of the carrier waves and the measured group velocity Cge of the packet are near the minimum point of the dispersion curve of group velocity, which may be the main reason why the packet can propagate with low diffusion.