Controller selection and placement in compressible turbulent flows By

Deciding how and where to control a fluid system often relies heavily on intuition, experience, and what actuators are readily available. While useful for flows for which experience exists, adopting such an approach for the control of novel, complex fluid systems may lead to suboptimal or ineffective control strategies. In this report we develop a procedure to use the structural sensitivity of a baseflow to estimate where an effective linear feedback controller might be placed without needing a priori knowledge. When applied to a simple high-subsonic diffuser, the method identifies candidate controller locations and types and demonstrates that the preferred locations depend on the type of controller and on the sensing variable.