Effects of propeller slipstream on aerodynamic performance of diamond joined-wing configuration UAV

The aerodynamic characteristics of the low Reynolds number diamond joined-wing configuration Unmanned Aerial Vehicle (UAV) with propellers is numerically simulated by quasi-steadily solving the Reynolds Averaged Navior-Stokes (RANS) equations of Multiple Reference Frames (MRF) based on the hybrid grid technology and k-k_L-ω transition model. The influence of the slipstream on the aerodynamic characteristics of the diamond joined-wing configuration UAV at different installation positions is studied by comparing the aerodynamic coefficients and the flow field characteristics of the UAV with propellers and with the clean configuration. The results show that the propeller slipstream does not always improve the lift characteristics of the UAV. The aerodynamic performance of the Aft-wing (after wing) is affected by the combination vortex formed by the propeller slipstream when the propeller is installed in the nose and Frt-wing (front wing). The effect of the propeller slipstream on the wing is also affected by the wing sweep angle and propeller rotation. Affected by layout characteristics, the propeller slipstream has a great influence on the pitching moment characteristics of the UAV when the installation position of the propeller is away from the focus.