Numerical Investigations of Camber-Morphed Flap-Elevator Systems in Trimmed Flight

Modern unmanned aerial vehicles (UAVs) demand improved aerodynamic performance and control authority. This study uses numerical simulations to compare the aerodynamic performance in longitudinal trim of two distinct control surface configurations that can be used in modern UAVs. The first configuration, the hinged system (HS), uses a traditional flap at 70% chord and a hinged elevator. The second, the smooth camber-morphed system (SCMS), features a camber-morphed flap from 70 to 90% chord and a camber-morphed elevator. The UAV wing section is the low-drag, asymmetric NACA [Formula: see text] airfoil, while the horizontal tail section is the symmetric NACA 0012 airfoil. Steady Reynolds-averaged Navier–Stokes simulations are performed using ANSYS Fluent v2023 R2, employing Menter’s shear stress transport [Formula: see text] turbulence model, coupled with the local-correlation based one-equation [Formula: see text]-transition model to capture laminar/turbulent transition effects. Simulations are carried out at Reynolds numbers of [Formula: see text] for takeoff/landing and [Formula: see text] for steady-level and low-speed cruise flight stages. Results indicate that the SCMS flap/elevator configuration results in reduced drag and improved longitudinal trim characteristics at desired lift during takeoff/landing and low-speed cruise flight, compared to the conventional hinged flap/elevator configuration (HS). However, during level flight (characterized by no flap deflection and nonzero elevator deflection for trim in both cases), both configurations exhibit very similar aerodynamic performance.