Numerical simulation of effect of steady blowing slot-less flap airfoil in ground effect

With growing requirements for the manufacturing cost, performance and reliability, and environment, the transport aircraft with bigger payload, shorter taking off and landing distance, and lower fuel consumption and aerodynamic noise is the development object of the future transport aircraft. Therefore, simple and efficient lift enhancement method is urgently needed. The method using blowing to enhance the lift is proved to be one of the most promising technologies. In the analysis of the performance of taking off and landing, ground effect must be considered, and it is thus essential to investigate the ground effect of the airfoil using blowing to enhance lift. The aerodynamic characteristics of slot-less flap airfoil with steady blowing in ground effect are investigated by numerical simulation. The results show that the lift and lift slope of the airfoil decrease obviously with steady blowing at small ride height compared with that far from the ground. The results also indicate that at small angles of attack, the lift increases firstly and then decreases with the decrease of ride height when blowing momentum coefficient is 0.005, but the lift monotonously decreases with the decrease of ride height when blowing momentum coefficient is 0.01. The phenomenon that the lift of the slot-less flap airfoil varies with the moment coefficients and the ride heights can directly affect the performance of taking off and landing, so it must be taken into consideration when applying blowing to increase the lift. © 2017, Press of Chinese Journal of Aeronautics. All right reserved.