Synergistic Enhancement of Fog Harvesting via Aerodynamic-Electrostatic Field-Assisted Transport on Bio-Inspired Spine Structures

Abstract

Freshwater scarcity is a critical global challenge, driving the development of high-efficiency atmospheric water harvesting technologies. While fog collection is a sustainable solution for arid regions, conventional passive systems are often limited by poor droplet interception and slow surface renewal. This work proposes a synergistic fog-harvesting strategy combining biomimetic cactus spines (BCS) with electrostatic and aerodynamic regulation: corona charging, airflow guidance, and Laplace pressure-driven transport on cones, which shortens shedding cycles and greatly improves harvesting efficiency. Systematic experiments and fluid dynamic simulations evaluated the influence of applied voltage, wind speed, windward angle, and geometry. The BCS achieved a peak collection rate of 390 mg/min at 18 kV and a wind speed of 2 m/s, representing a substantial enhancement over passive designs. Furthermore, the performance of longitudinal and radial BCS arrays was quantitatively analyzed, leading to a modified saturation model that accounts for airflow interference between adjacent units. The results further determine the optimal working parameters and array layout, which can parametrically adjust aerodynamic airflow regulation and improve droplet transport efficiency. This multi-field coupled design offers a feasible strategy for high-efficiency electric-assisted fog harvesting under complex practical environmental conditions.