Numerical Study of Aerodynamic Efficiency of a Wing in Simulated Rain Environment

Abstract

In this study, heavy rain effects on the aerodynamic efficiency of a NACA 0012 wing with an aspect ratio of 2 have been anticipated at a Reynolds number of . In the numerical simulation, the preprocessing software Gridgen has been used for creation of the geometry and generation of the mesh, and Fluent software is used as a solver. Discrete phase modeling in a Langrangian frame of reference has been used to simulate the rain particles dispersed in the continuous phase using a two-phase flow approach. The coupling between the two phases and its impact on both phases has been included. In this study, significant decrease in aerodynamic efficiency of the NACA 0012 three-dimensional wing has been observed. The lift and lift to drag ratio decreased up to for liquid water content of 30 and , respectively. The maximum decrease in lift has been observed for angle of attack of 6–14 deg, at which airplanes usually perform takeoff and landing. It is found that the heavy rain causes premature boundary-layer transition at low angle of attack and separation due to increase of shear stresses at high angle of attack. The water film layer formed on the surface of the wing and the splashed particles into the air are the main causes of the degradation in aerodynamic efficiency of the three-dimensional wing. The results obtained in the numerical study are compared with the experimental results, and they are in good agreement. This study will be useful for aviation engineers and scientists to design airplanes and unmanned aerial vehicles capable of flying in severe weather conditions.