Transient Flow Analysis and Static Bench Measurements for an Active Trailing-Edge Flap

Abstract

In this dissertation, several analyses over SNUF (Seoul National University Flap), a small-scaled prototype equipped with an active trailing edge flap, were conducted in order to achieve vibratory load reduction in the rotor system. The device consists of a piezoelectric actuator driven flap which generates secondary vibrations aimed at dampening the primary disturbances. Predictions of the hinge moment coefficient were retrieved through CFD (computational fluid dynamics) analyses in order to verify the capability of the chosen actuator to ensure a smooth and efficient displacement of the flap and therefore the achievement of the designated objective. The results showed good compromises between the actuator characteristics and the loads generated over the flap surface. Furthermore, a multibody dynamic analysis was implemented with DYMORE to obtain a holistic view of the forces and the displacements acting within the device when external aerodynamic loads and centrifugal force occur. Outcomes from the code were validated with theory formulation and thus are considered a reliable description of the dynamics of the system. In addition to that, a pulling test was conducted so as to observe any likely decrease in the deflection range once the centrifugal force acts in a direction perpendicular to the flap angular displacement. Although the ultimate load applied does not coincide with final objective, the limited shrinkage of the deflection span suggests a definitive result still satisfying the requirements.