Aerodynamic Characteristics of Airfoil Cruise Landing and High Lift Configurations in Simulated Rain Environment

Abstract

In this paper, heavy rain effects on the aerodynamic efficiency of National Advisory Committee for Aeronautics (NACA) 23015 airfoil cruise and landing configurations and NACA 64210 high lift configuration have been studied. For this study, preprocessing software Gridgen has been used for creation of geometry and mesh, and fluent software is used as a solver. Discrete phase modeling (DPM) in a Langrangian frame of reference has been used to simulate the rain particles dispersed in continuous phase using two-phase flow approach. The coupling between the two phases and its impact on both phases has been included. In discrete phase model (DPM), the wall film is modeled by the injected rain particles. In a simulated rain environment all the cruise, landing, and high lift configurations of airfoils showed a significant decrease in lift and increase in drag in heavy rain environment. In this study, it is found that the heavy rain causes premature boundary-layer transition at low angle of attack (AOA) and separation at high AOA. The water film layer formed on the surface of the airfoil is thought to alter the airfoil geometry and increase the mass effectively. In the simulation for NACA 23105 the increase in drag is less contrary to simulations done for NACA 64210 high lift configuration airfoil, for which the aerodynamic efficiency degradation is much higher. The relative differences appeared to be related to the susceptibility of each airfoil to premature boundary-layer transition. Postprocessing software like MATLAB, Tec plot, and Origin are used to see the effects of the heavy rain, and the results obtained are compared with the experimental results. It is strongly believed that this study will be useful for the aviation engineers and scientists to design the airplanes and UAVs capable of flying in severe weather conditions and to train the pilots to control the airplane in heavy rain conditions well.