Dynamic behavior of droplet impacting on superhydrophobic cylinder with different macro-ridge orientations

This study visually observed the dynamic behavior of water droplets impacting superhydrophobic cylinders with no texture, azimuthal macrotexture, and axial macrotexture. High-speed images were analyzed to compare droplet evolution, contact time, and the effect of impact velocity across surface configurations. Results showed droplet behavior differed significantly based on surface texture. On smooth cylinders, droplets spread, retracted, and rebounded as expected. However, when impacting cylinders with azimuthal ridges, droplets ruptured along the texture after reaching maximum spread and retracting briefly. Axial texturing caused droplets to burst into two during retraction. Contact time reduced more for axial versus azimuthal texturing. Rupturing transitions occurred for increasing Weber numbers with azimuthal texturing only. In summary, macro-ridge orientation and impact velocity influenced droplet dynamics and contact time upon impact. Further studies could advance understanding of surface tensions and inertial effects to inform both theory and applications of textured surfaces.