3D Fluid Dynamic and Aero-optical Characterization of Turret Geometry at Transonic and Supersonic Speeds (040550)

The Small Business Innovative Research (SBIR) Topic Number AF112-011 was initiated to investigate the effectiveness of passive and active flow control for mitigation of aero-optic shock effects. The SBIR Phase I effort measured the baseline flow around cylindrical and hemispherical turrets in transonic flows, began investigating the effect of passive flow control using an array of pins, and identified two active flow control approaches, reaching Technology Readiness Level (TRL) 2 (technology application formulated). The SBIR Phase II effort used subscale, two-dimensional geometries to demonstrate the effectiveness of both the passive and active flow control methods and to characterize the fundamental mechanisms. This work brought the methods up to TRL 3, proof of concept. The intent of the SBIR Phase III is to continue the logical path of work through the characterization and development using realistic, three-dimensional turret geometry at transonic flow conditions. This will serve to demonstrate the scalability of the actuation scheme and its effectiveness in three-dimensional flow. Tasks: - Surface Pressure Field using Pressure Sensitive Paint - Fluctuating Pressure Field using Fast Response Pressure Sensitive Paint - Force and Moment Measurements using a Strain Gage Balance - Three-dimensional Velocity Field Measurement using Particle Image Velocimetry (PIV) - Three-dimensional Density Field Measurement using Background-Oriented Schlieren (BOS) - Optical Distortion Measurements using Shack-Hartmann Sensor - Flow Diagnostic Experiments