1. CASE 1: TWO-DIMENSIONAL RANS SIMULATION OF A SYNTHETIC JET FLOW FIELD J. Cui and R. K. Agarwal Mechanical & Aerospace Engineering Department Washington University, St. Louis, MO 63130

2. Outline 1.Introduction 2.Software Employed 3.2D Simulations of a Synthetic Jet Flow Field  Grid and Modeling Issues  Results and Discussion 4.Conclusions of 2D Simulation Results 5.Preliminary 3D Simulations of a Synthetic Jet Flow Field 6.Future Work

3. Motivation for Active Flow Control  In recent years, it has been surmised that the fluidic modification of aerodynamic and propulsive flow fields can cover multiple flight regimes without the need of conventional control surfaces such as flaps, spoilers and variable wing sweep.  The fluidic modification (or flow control) can be accomplished by employing micro-surface effectors and other fluidic devices dynamically operated by an intelligent control system.  These new “flow control” technologies thus have the potential of resulting in radical improvement in aircraft performance and weight reduction.

4. Flow Control with Synthetic Jets  Virtual Aerodynamic Shape Modification of an Airfoil Using a Synthetic Jet Actuator (AIAA 03-4158)  Vectoring Control of a Primary Jet with Synthetic Jets (AIAA 02-3284)  Control of Recirculating Flow Region Behind a Backward Facing Step Using Synthetic Jets (AIAA 03-1125)  Interaction of a Synthetic Jet with a Flat Plate Turbulent Boundary Layer (AIAA 03-3458)  Flow Control of Shear Layers Over 2-D Cavities Using Pulsed Jet (AIAA 04-428)

5. CFD Flow-Solver Employed  WIND  structured, multi-zone, compressible RANS solver  2 nd or higher-order upwind/central differencing  Four-stage Runge-Kutta time stepping  Spalart-Allmaras (SA), Mentor’s SST, combined SST & LES, and k-ε turbulence models

6. Grid Employed Whole view Zoomed in: the grid of the slot Zone 1 (33  86) Zone 2 (62  50 ) Zone 3 (41  65) Zone 4 (197  139) Diaphragm

7. Boundary Conditions  External Flow Region (zone 4) – Bottom wall (except SJ)no-slip – All other three boundariesoutflow  SJ Actuator (zone 1, 2 & 3) – At the diaphragmarbitrary inflow – All other boundariescoupled or no-slip wall  At the Diaphragm (zone 1, I=1)

8. Justification of Boundary Conditions Mass-flux at the diaphragm & SJ slot Pressure inside the cavity

9. Phase-averaged v -velocity at ( x, y ) = (0, 0.1 mm) Justification of Boundary Conditions (cont.)

10. Time-step & Grid Independence Studies Long-time averaged v -velocity along the centerline Phase-averaged v -velocity at (0, 2mm)

11. Long-time Averaged v- Velocity along the Centerline (a) v -velocity along the centerline (b) Zoomed-in view: near the wall

12. Long-time Averaged v- Velocity along x- Axis y = 0.1mm y = 1mm

13. Averaged Jet Width & Phase-Averaged v- Velocity Averaged jet width Phase-averaged v -velocity Averaged jet width Phase-averaged v -velocity

14. Phase-Averaged Velocity Contours (u at 45  ) PIV dataSSTSST_LESSA

15. Phase-Averaged Velocity Contours (v at 45  ) PIV dataSSTSST_LESSA

16. Phase-Averaged Velocity Contours (u at 90  ) PIV dataSSTSST_LESSA

17. Phase-Averaged Velocity Contours (v at 90  ) PIV dataSSTSST_LESSA

18. Phase-Averaged Velocity Contours (v at 135  ) PIV dataSSTSST_LESSA

19. Phase-Averaged Velocity Contours (v at 225  ) PIV dataSSTSST_LESSA

20. Conclusions of 2D Simulation Conclusions of 2D Simulation Results  2D RANS simulations (SST, SST_LES, SA) and experiments have reasonable agreement in capturing the overall features of the flow field.  SST model gives the best result out of three simulations

21. Preliminary 3D Simulations  Grids  Modeling issues (same as in 2D simulations)  Results and discussions

22. Grid Employed Whole view (9 zones) Zoomed in: the grid of the slot Diaphragm Zone 2 (19  19  51 ) Zone 1 (73  11  17) Zone 3 (29  61  35) x y z y x 4 5 6 7 8 9 zone4/85/967 # pts39,52531,875165,075133,125

23. Long-time Averaged v -Velocity along the Centerline

24. Long-time Averaged v- Velocity along x- Axis y = 0.1mm y = 1mm

25. Averaged Jet Width & Phase-Averaged v- Velocity Averaged jet width Phase-averaged v -velocity Averaged jet width Phase-averaged v -velocity

26. Phase-Averaged Velocity Contours ( u, v at 45  ) PIV data2D SST3D SST uvuv

27. Phase-Averaged Velocity Contours ( u, v at 90  ) PIV data2D SST3D SST uvuv

28. Phase-Averaged Velocity Contours ( v at 135 , 225  ) PIV data2D SST3D SST 135  225 

29. 3D Simulation of Case1– u,v,w Contours at 45 

30. 3D Simulation of Case1– u,v,w Contours at 90 

31. Future Work  3D simulations of case1: time-step and grid refinement study  3D simulations of case 2: synthetic jet interacts with cross flow