Aerodynamic efficacy of adding yaw-wise rotational degree of freedom to an airplane flap

Abstract

This study scrutinized the aerodynamic change of adding a yaw-wise rotational degree of freedom to a single slotted flap of airplane via computational fluid dynamic analyses. Existing slotted flaps have spanwise constant gaps and are disharmonious with the 3D nature of the flow field. A flap geometry and its angle condition are sensitive to aerodynamic performance; small variations in them must be useful in aerodynamic improvement. To add the yaw-wise rotation to a flap is a lower hurdle than to attain other high-lift systems. Therefore, after defining a simple configuration consisting of a fuselage, a wing, and a single slotted flap, we investigated the mesh dependency to consider the diversity in flow phenomena precisely; we examined the effect of the yaw-wise rotation for the flap on improving the whole lift. To place the flap at suitable yaw-wise rotation angles consequently effected raising the lift. We revealed the physical mechanism that accelerating the fluid in the gap between the wing and the flap changes the separation structure on the flap upper surface and grows the lift.