Fig. 7.

Effectiveness of three-mode planar turns in crawling/burrowing and swimming. (A) Definition of the turn angle ${\theta }^{\text{turn}}$ and positions of the turn mode-switching points $s_1^c$ and $s_2^c=s_1^c+\mathrm{\Delta }{s}^c$ for the PHC maneuvers shown. We use $q{s}_1^c=3\pi /2$, $q\mathrm{\Delta }{s}^c=0.6$, and default mode amplitude $A_1/q=1$ for all calculations shown. (B) Three-mode planar turn trajectories and snapshots of body postures (thick trail segments, $qL=5.5$) for a nematode crawling/burrowing without transverse slip and with turning-mode amplitude $A_2/q$ as labeled. (C) A sequence of simulation snapshots of a swimming C-shaped nematode ($qL=5.5$) performing a three-mode PHC turn, with the turning mode amplitude as labeled. (D) Comparison of the dependence of the turn angle ${\theta }^{\text{turn}}$ (in degrees) on the turning-mode amplitude $A_2/q$ for motion without transverse slip (dashed line) and swimming (solid line). The three circles for each case correspond to the shown trajectories and snapshots.