You are invited to a

featuring presentations by 3 AE students:

Arjun Krishnan & Ashwin Krishan

"World’s First Flight Demonstration  of Aero-Effected Bleed Air Roll Control "

and

Komahan Boopathy

“Adjoint-Based Derivative Evaluation Methods for Flexible Multibody Systems ”

"World’s First Flight Demonstration  of Aero-Effected Bleed Air Roll Control "

Hinged flaps are archetypical scheme of effecting control forces and moments in fixed wing aircraft. Aero-effected bleed air offers an alternate means of controlling aircraft and has advantages over the hinged flap in certain types of aircraft. Unlike other flow control technologies, the energy for aero-effected bleed air control is derived from the motion of the vehicle. The idea is to have multiple pores on the top and bottom surfaces of a wing. By opening channels between these pores using low power actuators, it is possible to exploit inherent pressure differences to create an ejection or suction that interacts with the local cross flow, causing a change in local pressure. Effected across a section of wing, it results in a force or moment that can be used to control an aircraft. Wind tunnel experiments have demonstrated the technology's ability to generate rolling moments equivalent to those of ailerons with minimal drag penalty. The Georgia Tech CAMM Lab FLD-25 is the world’s first fixed wing aircraft to demonstrate aero-effected bleed air roll control in flight. The aircraft achieved roll rates of 100 deg/s at cruise velocity with extremely low power actuators. Our presentation will discuss the development of the aircraft, the data gathered and the path forward including potential applicability of this technology.

"World’s First Flight Demonstration  of Aero-Effected Bleed Air Roll Control"

Adjoint formulations are central to many modern algorithms for sensitivity analysis, gradient-based design optimization, mesh refinement, optimal control and error estimation. With the adjoint-method, the computational cost in evaluating the derivatives is nearly independent of the number of design variables in the problem. Adjoint-based derivative evaluation methods for second-order systems arising in flexible multibody dynamics are presented. The governing equations of motion are solved using implicit time marching schemes: backward difference formulae, diagonally implicit Runge-Kutta, Newmark-Beta-Gamma and Adams-Bashforth-Moulton methods. The time-dependent discrete adjoint for these methods are presented along with complex-step verification of the derivatives.