Figure 13.

(a) Beetle skin surface revealing presence of domes/dimples and grooves [196]; (b) schematic diagram of smooth surface and beetle-inspired surface domes in erosion wear [41]; (c) schematic diagram of the interaction between tamarisk-inspired surface V-grooves and erodent particles [193]; and (d) schematic diagram of the interaction between desert scorpion-inspired grooved surface and erodent particles. Occurrence of rotational flow (vortex) for the impact velocity of particles (Vo), which forms the upward velocity vector perpendicular to the surface (V). The vertical upward velocity V is opposite to the velocity component Voy of the particle in the normal direction, which can slow the normal velocity of the solid particles. Studies show that, even if the rotational flow velocity is small, it still plays a very important role in reducing erosion wear [186]. All images were reproduced with permission.