Surface Measurements – Flow Field Correlations Resulting in Applicable Cavity Flow Field Control

A surface pressure measurement based closed loop adaptive flow control strategy for the minimization of dynamic loads caused by high subsonic/supersonic flow over a cavity is proposed. In the Phase I part of this program we have focused on the examining the feasibility of this approach and establishing some of the basic techniques to be used in the control algorithm. The validity of using a limited number of wall pressure measurements as an indicator of the entire cavity flow field dynamics is established, its temporal analog is shown to be equivalent to an ARMA system identification model and its use in a predictive manner to estimate future states of the system is demonstrated. This, along with a Disturbance Rejection based controller and a plant model in the form of a validated CFD solver is used to create a numerical test bed. This presents a low risk approach to the Phase II where we will focus the issues of controller design, actuator characterization, design and refinement, and, demonstration of flow control on a cavity flow field at a suitable scale.