11 1 CFDVAL Langley Research Center Workshop CFD Validation of Synthetic Jets and Turbulent Separation Control Woodlands Hotel and Conference Center Colonial Williamsburg, Williamsburg, Virginia, USA March 29-31, 2004 George Huang, Raymond LeBeau, Hua Chen, Liang Huang, Vamsidhar Katam, Vimal Parimi and Yih-Nen Jeng Department of Mechanical Engineering University of Kentucky Lexington, KY

22 2 CFD Codes GHOST –In-house 2D structured multi- block overlapping code –QUICK scheme for mean flow equations TVD for turbulence equations –2 nd order backward time stepping –Incompressible flow solver using SIMPLE approach –SST turbulence model –MPI parallelization –Well validated for a wide range of flow conditions.

33 3 Computer Codes UNCLE –In-house 2-D and 3-D unstructured code –2 nd order upwind scheme –2 nd order backward time stepping –Incompressible flow solver using SIMPLE approach –Domain decomposition using METIS –SST turbulence model –MPI parallelization –Only validated for a limit number of cases.

44 4 Case 1 Re =2458 T =  T = (2880 steps per cycle) Average is taken after 5 cycles Ensemble averaging - Coarse grid 3 cycle and fine grid 1 cycle

55 5 Actuator Motion Case1

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15 Possible Causes Diaphragm movement vs. piston motion 2D vs. 3D –Mass conservation –3D effects Modeling approach Inlet velocity shift Chamber vs. outflow

16 Power Spectrum of the Actuator Case 1

Degree Phase Waves

18 Decomposition of 360-Degree Wave