Iranian researchers model PV panel tilt and wind effects on hail impact severity
A computational model shows that wind direction and tilt angle alter perpendicular kinetic energy during hail strikes on solar modules.
Researchers from Shahrood University of Technology, Radsun Energy Pars, and Asoo Vision Pardaz in Iran have developed a computational model to evaluate hailstone trajectories and impact mechanics on photovoltaic modules, pv-magazine.com reported. The team simulated spherical hailstones measuring 1 cm to 10 cm falling from an initial altitude of 2,000 m under wind speeds ranging from 1 m/s to 50 m/s 
pv-magazine.compv-magazine.compv-magazine.comOpen source ↗. The governing aerodynamic and gravitational equations were solved using the fourth-order Runge–Kutta method under constant air and ice densities.
To evaluate localized environmental risks, the authors analyzed meteorological data collected from 2004 to 2024 for a 3 MW solar installation located in Takestan, Iran pv-magazine.compv-magazine.compv-magazine.comOpen source ↗. They compared panel tilt angles of 25° and 30° across four specific wind scenarios: 22.8 m/s from 350°, alongside 24 m/s from 200°, 350°, and 360° pv-magazine.compv-magazine.compv-magazine.comOpen source ↗.
Aerodynamic drag calculations
The simulation revealed that assuming a constant drag coefficient creates substantial numerical errors for larger particles pv-magazine.compv-magazine.compv-magazine.comOpen source ↗. For hailstones with diameters of 8 cm or greater, using a constant drag coefficient yielded deviations of up to approximately 14% compared to calculations that incorporated Reynolds-number-dependent drag coefficients, according to corresponding author Armin Hasanpour pv-magazine.compv-magazine.compv-magazine.comOpen source ↗.
Calculated impact velocities were projected normal to the panel surface to compute the perpendicular component of kinetic energy pv-magazine.compv-magazine.compv-magazine.comOpen source ↗. The researchers evaluated potential mechanical cracking and indentation using a conceptual damage model based on an assumed critical threshold of 2 J, validating the outputs against angle-adjusted theoretical energy calculations pv-magazine.compv-magazine.compv-magazine.comOpen source ↗.
Directional wind and tilt dynamics
The findings indicated that wind speed alone cannot predict hail damage severity pv-magazine.compv-magazine.compv-magazine.comOpen source ↗. Hasanpour stated that the interaction between wind direction, horizontal wind velocity, and panel azimuth alters the incident impact angle and distributed kinetic energy across the glass surface pv-magazine.compv-magazine.compv-magazine.comOpen source ↗.
Adjusting the module tilt from 25° to 30° shifted the perpendicular kinetic energy load delivered by incoming hailstones under identical wind conditions pv-magazine.compv-magazine.compv-magazine.comOpen source ↗. The authors concluded that photovoltaic racking orientation and tilt angles must balance electrical yield optimization with site-specific hail trajectories and local atmospheric patterns pv-magazine.compv-magazine.compv-magazine.comOpen source ↗.
