Figure 2. Asymmetric bouncing on bio-inspired asymmetric surface.

(a) The variations of contact line length in the axial and azimuthal directions as a function of time. The drop continues spreading in the azimuthal direction after it reaches its maximum extension in the axial direction at 3.8 ms. While retracting in the axial direction, the lateral extension in the azimuthal direction remains almost constant. (b–d) The variation of the k (defined as the ratio of the maximum spreading diameters in the azimuthal and axial directions), the contact time, the axial spreading time t₁ (left) and axial retraction time t₂ (right) as a function of surface curvature D (normalized by drop radius D₀) under different We.