Surface-swimming organisms generate a diversity of wave patterns. By analyzing the wakes produced by two juvenile snakes, we show that their surface wave patterns depart significantly from classical predictions for uniform rectilinear motion. Using a simplified model of a slaloming pressure disturbance, we reproduce these wave patterns and demonstrate, both theoretically and experimentally, that they are composed of the spatiotemporal signature of a uniformly translating pulsating source. Our analysis of the mean wave drag reveals in particular that lateral oscillations of the head can reduce the drag when $U>c_{\min }$, where $c_{\min }$ is the minimal phase velocity. In addition, two secondary wave-drag peaks appear at velocities below and above $c_{\min }$, coinciding with the formation of V-shaped wakes from pulsating sources. We show that these transitions result from changes in the resonance conditions of translating pulsating waves, fundamentally redefining the threshold for the formation of unsteady wakes. This key observation enables the construction of a phase diagram of capillary-gravity waves generated by nonuniformly moving bodies.

Close

PrevNext

View figure in article

• Surface gravity waves
• Swimming