A dynamic contact angle model was used to simulate droplet shedding on various wettability surfaces. The changes in drag and lift forces before and after droplet coalescence were also analyzed in detail to better explain the dynamic behavior of droplets. [PERSON] et al. [21] focused on the differences in the behavior of droplets of different volumes on hydrophilic and superhydrophobic surfaces under airflow. It was found that larger droplets on hydrophilic surfaces exhibited longer wetting lengths and stronger adhesion, and that the air velocity was the main reason affecting the sliding and rolling behavior of droplets on superhydrophobic surfaces. Only a few studies have explored the motion of droplets adhered to inclined surfaces in airflow, primarily concentrating on the forces exerted on droplets. [PERSON] et al. [22] investigated the acceleration of droplets moving in uniform airflows on the windshield by building a wind tunnel. They found that droplets can be classified as sliding, stationary, and climbing at different airflow velocities. [PERSON] et al. [23] simulated the behavior of droplets on a hydrophobic windshield under driving conditions and proposed a force equation for droplets during the movement. [PERSON] et al. [24] proposed a new method to simulate the water flow of droplets on a tilted glass pane at the moment of rainfall and proved the reliability of the simulation compared with the experimental results. [PERSON] [25] used a graphical processing method to simulate the behavior of droplets on a tilted windshield under different combinations of wind and gravity. Correlation between the wind force magnitude and droplet motion was obtained. [PERSON] et al. [26] proposed a mathematical model for the detachment of droplets on inclined surfaces under high-speed airflow, employing direct formulas for surface tension, gravity, and aerodynamic forces. This model plays a crucial role in predicting the critical air velocity. [PERSON] et al. [27] investigated the droplet shedding behavior on metal fiber surfaces with different surface wettability and tilting angles and established predictive correlations for critical droplet sizes on metal fibers with different wettability and different tilting angles, which agreed with the experimental results. [PERSON] et al. [28] considered factors like droplet shape and airspeed in their research into droplet motion on inclined surfaces under airflow. They developed a predictive model for the air resistance coefficient that adapts to changes in influencing factors, making it useful for calculating critical air velocity. In conclusion, current studies on the detachment behavior of droplets adhering to flat and inclined surfaces in airflow, as well as the forces acting on droplets in an airflow environment, have made significant progress. However, these studies primarily focus on predicting the numerical values of critical air velocity. The forces acting on droplets and their shape changes when they start moving have not been explored. In this study, the coupled CLSVOF method, integrating Volume of Fluid (VOF) and Level-set method, is used for numerical simulation. A three-dimensional wind tunnel model has been developed, and a dynamic contact angle model is employed to accurately simulate the changes in droplets. By considering airflow velocity and droplet size as research variables, the study offers a comprehensive analysis of how these variables influence the motion patterns and shape transformation rules of droplets adhering to inclined windshields. Finally, forces acting on the droplet are calculated. The changes in droplet forces with time are discussed, and the relationship between the dominant force of droplet movement and other resistances is compared.