Shear-driven off-plane detachment of water drops from superhydrophobic surfaces

Shear-driven drop motion is a common phenomenon with critical implications for applications such as aircraft anti-icing, where efficient drop detachment is essential to reduce water retention, limit freezing, and suppress subsequent ice accumulation. While tangential air shear is typically associated with in-plane drop motion, it has not been considered effective for inducing detachment. Here, combing experiments, simulations and theoretical analysis, we demonstrate that off-plane drop detachment can occur under specific conditions determined by surface wettability, drop radius, and wind speed. Notably, we identify a distinct scaling regime for the critical wind speed required for detachment as a function of drop radius, determined by the balance between lift and restoring force. Our findings advance the fundamental understanding of drop-airflow interactions and offer inspiring design strategies for efficient drop removal.