Frequency shift and aspect ratio of a rotating-oscillating liquid droplet

We study the shape oscillations of a rotating liquid droplet numerically. The relation between the aspect ratio of the droplet shape and the frequency shift is made clear, and the large-amplitude oscillations with no frequency shift are demonstrated to be possible. Our results indicate that the accurate measurement of oscillation frequencies, which are not suffered from frequency shift, could be conducted by controlling the rotation rate and the amplitude, and thus more reliable surface tension would be obtained.