Fig. 2: Spectral analysis of droplet variables.

The time series of (a) translational step size Δr, (b) change in direction of motion Δθ, and (c) droplet aspect ratio or deformation parameter A, respectively. d–f Corresponding power spectrum of the time series shown in (a–c). The spectrum in panel (d) implies that two consecutive droplet position increments are not independent and thus the case is different from standard Brownian increments because Brownian increments are known to be independent. Similarly, panel (e) implies that two consecutive Δθ are not independent. The spectrum of the time series of aspect ratio A indicates that the droplet deformations have underlying oscillatory features. The solid black lines in (d–f) are a guide to the eye.