Experimental study on the influence of turbulence on hail impacts

Abstract

Hailstorms, characterized by their intensity, are often accompanied by strong winds and heavy rain, posing significant destructive potential. Data indicate that the economic losses caused by hail to buildings, particularly solar panels, have been increasing annually. However, research on the hail resistance of photovoltaic panels has predominantly focused on the isolated effects of hail impacts and wind loads, neglecting the coupling effects between wind and hail. In this study, a device was designed to couple both wind and hail. The effects of turbulence, hail size, and velocity on hail impact behavior were systematically studied and quantified. A predictive formula for the peak load of hail impact on structures was established. The results indicate that the impact of turbulence on hail is significant. When turbulence intensity varies with hail velocity, hail impact force increases as turbulence decreases and hail velocity increases. When both turbulence and hail diameter vary, the impact force of smaller hailstones shows less variation with increasing turbulence. According to variance analysis, hail velocity is the most significant factor affecting hail impact, followed by hail diameter and finally turbulence. The regression equation is given by $F=-0.624I_{\text{u}}+5116.25D+7.85V_{\mathit{hail}}-259.709$, where $F$ represents the peak impact force in Newtons (N), $I_{\text{u}}$ denotes the turbulence intensity, $D$ is the hail diameter in meters (m), and $V_{\mathit{hail}}$ is the hail velocity in meters per second (m/s).