Fig. 4.

(A) Snapshots of the nutrient concentration fields around a model swimmer for Pe^U = 7 at successive times computed by solving Eq. 4 numerically. The top row corresponds to the undulatory stroke A, which we computed as a local optimal for and the bottom row to the breaststroke E, which is the optimal stroke found for . (B) Loglog plot of Sh versus Pe^U = 7. The inset corresponds to a semilogarithmic plot of the ratio of Sh computed for stroke D and E divided by Sh for stroke A as a function of Pe^U = 7. (C) Loglog plot of Sh versus Pe^ϕ. The inset corresponds to a semilog plot of Sh/Sh_A versus Pe^ϕ.