Session: SYMP 6-10: Reservoir Computing and Control

Paper Number: 139944

139944 - The Physics of Bio-inspired Covert Flaps as Flight Control Devices 

Blended Wing Body (BWB) aircraft are desired configurations because they improve efficiency and increase cargo volume. However, they have reduced control authority and maneuverability. This is mainly due to the lack of a conventional tail section, which reduces lateral and directional stability. Birds, the biological counterpart of the BWB, also lack a conventional vertical stabilizer, yet they still maintain superior control authority during flight maneuvers. This improved performance can be attributed to shape changes in the tail and wing (i.e., changes in sweep, dihedral, and twist) and feather systems’ deflections on the wing’s surface. One of such feather systems is the coverts, which are contour feathers found on the upper and lower surfaces of a bird's wing. The authors have previously studied coverts as passive flow-control devices and 2D flight-control devices. The 2D coverts have been found to have a greater response envelope when deflected simultaneously on the upper and lower surfaces of a NACA 2414 airfoil, which matches behaviors observed in nature. Further, we isolated how each input parameter (flap locations and flap deflection angles) affects the responses (lift, drag, and pitching moment). In this paper, we expand the understanding of the covert-inspired flap system from 2D to 3D by studying the effect of the flaps on the aerodynamic response when deflected asymmetrically between the right and left wing. More specifically, we will use Princeton’s ultra-low turbulence wind tunnel to study the effect of varying the flow angles (i.e., angle of attack and side slip) on the aircraft’s pitch, roll, and yaw. Moreover, we will characterize the flap performance as a function of variations in flap locations and deflection angles. Finally, we will propose a conversion factor from 2D to 3D that accounts for the aspect ratio of the 3D wing. Our approach is an integrated approach that starts with carefully selecting the test points using the Design of Experiment (DoE); after that, the force-moment data will be augmented with Data-Driven Models (DDM) and Physics-based Understanding (PU) using Particle Image Velocimetry (PIV) of the flow field. This is a new iterative approach that reduces experimental costs and time limitations. The integrated approach makes an extremely large design space explorable by choosing the critical points that describe the response behavior and interactions of input parameters without having to explore each available point or change one parameter at a time. Further, the integrated approach derives an objectively good fit model for the responses without losing the physical insight behind the numbers.

Presenting Author: Diaa Zekry Princeton University

Presenting Author Biography: Diaa Zekry is a Ph.D. Candidate at Princeton University. He is passionate about the aerodynamics of bio-inspired systems and system identification of flying systems.

Authors:

Diaa Zekry
Aimy Wissa