Aeroelastic structural acoustic coupling: Implications on the control of turbulent boundary-layer noise transmission

Abstract

A method of formulating a model to evaluate the aeroelastic structural acoustic response of a panel subjected to turbulent boundary layer (TBL) noise sources and coupled with full potential flow aerodynamics is presented. Reduced-order models of both the aerodynamics and the structural acoustic coupling are presented such that a state-variable realization of the entire system dynamics can be developed for future active control system design and synthesis with modern and robust control theory. Results from this study demonstrate the importance of including aeroelastic coupling in modeling the structural acoustic response of panels for interior noise control on modern aircraft. At subsonic flow conditions, the aeroelastic coupling serves to increase the transmission loss across the panel with increasing Mach number; however, the power spectrum of the TBL noise source increases with increasing Mach number as well and thus offsets this benefit to some degree. Results from this study also serve to demonstrate that for future analysis of robust stability and performance, variations in the plant dynamics due to variations in flow conditions must be considered in the design of broadband, feedback, active structural acoustic control systems.

A Wavenumber Approach to Modelling the Response of a Randomly Excited Panel, Part I: General Theory

“…However, we limit our predictions to Mach numbers lower than 0)8, as the external radiation damping can still be considered as negligible with respect to the internal radiation damping and the mechanical damping of the plate in this Mach number range. For transonic and supersonic Mach numbers, it can be shown that the aeroelastic structural acoustic coupling has a signi"cant in#uence on the sound power inwardly radiated [21].…”

A Wavenumber Approach to Modelling the Response of a Randomly Excited Panel, Part Ii: Application to Aircraft Panels Excited by a Turbulent Boundary Layer

“…An important point is to know the parameter range over which the in#uence of aeroelastic coupling can be neglected. This point is addressed in reference [15]. It is shown that, for a typical aircraft panel, up to Mach number of 0)7, the aerodynamic damping e!ect can still be neglected without signi"cantly a!ecting the dynamics of the system.…”

Elimination of First Order Errors in Shock Calculations

“…Phenomena that require very high resolution, i.e., high order finite difference methods, occur in applications such as electromagnetics, acoustics (in fact, all cases of wave propagation), and direct simulation of turbulent and transitional flow (see, for example, [3], [6], [14], [15], [16], [17], [18], [19], [20]). The small scale behavior is of significance in the applications above, and the phenomena involved cannot be captured without an appropriate resolution of this fine scale.…”