Fig. 7.

Trajectories of the last immersed boundary point at the end of the flagellum for nondimensional time t =0–85. Top row: with CatSper mediated Ca²⁺ dynamics, (a) constant S₁, (b) linear taper of S₁, (c) fourth order taper of S₁. Bottom row: no CatSper mediated Ca²⁺ dynamics, i.e. with constant resting level of Ca²⁺ concentration, (d) constant S₁, (e) linear taper of S₁, (f) fourth order taper of S₁. Arrows denote initial starting location and initial direction. All simulations are with k_A=0.3 if ζ(s, t) > 0 and k_A = 0.5 if ζ(s, t) < 0.