Fig. 6. Universal scaling of the rheotactic velocity.

(A) Dependence of the scaled mean rheotactic velocity v_y/v₀ on the shear rate $\stackrel{.}{\mathrm{\gamma }}$ for nontumbling bacteria in simple shear (simulations) for different parameter sets (rotational diffusion D_r, bacterium aspect ratio α, chiral strength ν). (B) Results as shown in (A) but plotted against the chirality number 𝒞. (C) Data in (B) for α = 5 compared to tumbling bacteria in simple shear flow and Poiseuille flow. (D) Slow algebraic saturation at high shear rates. Color code indicated in (D). Symbol code used in all subfigures: ⋆D_r = 0.057, α = 5, ν = 0.06; ▯D_r = 0.057, α = 5, ν = 0.006; ○D_r = 0.2, α = 5, ν = 0.06; △D_r = 0.057, α = 5, ν = 0.02; ▽D_r = 0.057, α = 5, ν = 0.1; ⊳D_r = 0.1, α = 5, ν = 0.06; ◊D_r = 0.057, α = 3, ν = 0.06; □D_r = 0.057, α = 10, ν = 0.06.