1. 60 th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Control and Scaling of Radius-Vectored Turbulent Boundary Layers Using Plasma Actuators T. Corke and R. Hewitt Center for Flow Physics and Control Aerospace and Mechanical Engineering University of Notre Dame

2. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Objectives:  Investigate physics and scaling of SDBD Plasma Actuators for flow separation control on TE radii. Parameters: Radius, TBL thickness, free- stream speed.  Develop designs for flow separation control associated with airframe noise.

3. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Motivation: Airframe Noise Control -13.3 dB

4. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah SDBD Plasma Actuators Prog. Aero. Sci., 2007 (In press). Ref: AIAA J., 42, 3, 2004 exposed electrode dielectric AC voltage source covered electrode substrate Induced Flow

5. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Coanda Effect: No external flow Plasma actuator (90 deg.) Plasma-induced Coanda effect Plasma actuators Plasma Actuators (90 & 270 deg.)

6. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Coanda Effect No External Flow

7. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Experimental Approach: Effect of External Flow

8. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Experimental Setup Flow Light Sheet

9. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Particle Visualization R=10.4 cm (4.1in) U ∞ =6 m/s Baseline

10. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Particle Visualization 15.2kV

11. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Particle Visualization 18.6kV

12. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Particle Visualization 22.4kV

13. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Particle Visualization 25.5kV

14. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Particle Visualization 28.5kV

15. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Surface Flow Visualization  Measurements of separation location was done using surface flow visualization Mixture of evaporating oil and china clay. Applied on radius surface Oil moves according to local wall shear stress.

16. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Separation Location Summary: Min. Sensitivity to FS Velocity. Baseline separation location moves upstream with decreasing radius. Linear dependence of x s on actuator voltage xsxs Decreasing R

17. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Flow Turning Angle Summary: Min. Sensitivity to FS Velocity. Response of Actuator increases with decreasing radius  =x s /R Decreasing R

18. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Results: Flow Turning Angle Decreasing R

19. 60th Annual Meeting of the APS Division of Fluid Dynamics Salt Lake City, Utah Summary:  SDBD plasma actuators effective in controlling flow separation around a trailing-edge radius in which the approaching flow is a turbulent boundary layer.  Minimum Sensitivity to Free-stream Velocity. Baseline separation location moves upstream with decreasing radius. Linear dependence of xs on actuator voltage.  Response of Actuator increases with decreasing radius.  Minimum sensitivity to TBL thickness.  Up to 50% recovery of wake momentum in experiment. Smaller radii more effective.