Flow Control for Altering Aero-Optical Characteristics of Turbulent Flows and Associated Sensor for Validation

This Phase I proposal describes concepts to force a turbulent flow and its associated optical distortion into a state that is more favorable for aero-optical management. The project will produce a unique capability to model, test, and analyze the effectiveness of flow control in minimizing aero-optical degradation of wavefronts. We will examine and compare the effects of flow forcing at both high and low frequencies, and quantify the effects by performing high spatial resolution wavefront measurements. The basic idea is that by forcing the large scale structure of turbulent flow into a predictable state we can develop an optimal procedure for mitigating aero-optical distortion; for example, with adaptive optics. The proposed Phase I work will demonstrate that we can provide the U.S. Air Force with a unique capability to understand and exploit the relationship between flow control mechanisms and aero-optics. Moreover, it will begin the actual assessment, comparison and down selection of a specific flow control concept. The project includes an experimental demonstration in a wind tunnel, in which the effect of flow control on aero-optical properties of the flow will be quantified through the use of digital phase shifting interferometry.