1 Synchronization in Aeroelastic and Flow Control Problems: Computations and Experimental Investigations Robert Bruce Alstrom 1 , Goodarz Ahmadi 2 , Erik Bollt 3 , Pier Marzocca 4 Clarkson University, Potsdam, New York 13699-5725 EXTENDED ABSTRACT With in the field of aerospace engineering, there are a number of flow induced vibration problems that pose significant airworthiness risks to flight vehicles; in particular high performance aircraft. One of the more prevalent external aero-mechanical instabilities is aerodynamic buffeting. Aerodynamic buffeting affects a wide range of aircraft their structures, particularly high performance aircraft. For example, buffeting has proven to be a significant airworthiness issue for twined tailed fighter aircraft such as the F/A-18 Hornet, F-15 Eagle and the F/A-22 Raptor [1]. Buffeting typically occurs at high angle-of-attack and is induced primarily by forebody vortex shedding. In addition to twin tailed fighter aircraft, the F-16 has experienced severe vertical fin damage (i.e. partial or complete loss of aero-surface) due to buffet; spillage of inlet turbulence during high speed abrupt decelerations was sighted as the cause of buffeting. In the early 1980s, the Low Altitude Navigation and Targeting Infrared for Night (LANTIRN) pod was place ahead of the vertical fins as shown if Figure 1. Figure 1 Location of vertical fins and LANTIRN Pods [1] As a result of the turbulent wake shed by the pods, the vertical fins experienced buffeting, which subsequently led to cracking and structural failure. These are but a few examples of how aerodynamic induced vibration, often appearing in the form of chaotic behavior, can be detrimental to flight safety. A number of solutions to this problem have been investigated; they include piezoelectric patch actuators under closed-loop control and active wake control via synthetic jet actuators. In a joint effort, Lockheed Martin, the Airforce Institute of Technology 1 Graduate Student, Department of Mechanical and Aeronautical Engineering, AIAA Senior Member 2 Professor, Department of Mechanical and Aeronautical Engineering 3 Professor, Department of Mathematics and Computer Science 4 Associate Professor, Department of Mechanical and Aeronautical Engineering, AIAA Senior Member