Figure 4

Membrane shape for elongated swimmers.

(a) Asphericity parameter for N_b = 50 (blue symbols), N_b = 100 (red symbols) and N_b = 150 (green symbols). The lines are a guide to the eye. With increasing ϕ the vesicle approaches an average circular shape (Δ ~ 0). (b) The red circles are (R_g − R₀)/R_g, the red line is a guide to the eye, the black squares represent PN_b/2πk. The data are plotted as a function of the area fraction computed with respect the circle of radius R_g for N_b = 150. (c) The probability distribution of the local curvatures undergoes a crossover from single to double peacked shape by increasing ϕ (in figure from 0.16 (blue) to 0.83 (red)). (d) To quantify the bimodal character of the distribution we look at the Sarle’s bimodality coefficient β as a function of ϕ for N_b = 50, 100, 150 (blue, red and green), the black dashed line is β for a Gaussian distribution. The grey area represents the estimated ϕ_c range. Inset: ϕ_c obtained from the decoupling between pressure and deformation (blue symbols) the line is the estimate of ϕ_c given by ϕ(N_b = N_s).