1. Adaptation Workshop > 21.06.2006 Folie 1 > TAU Adaptation on EC145 > Britta Schöning TAU Adaptation for EC145 Helicopter Fuselage Britta Schöning DLR – Inst. für Aerodynamik und Strömungstechnik Alessandro D‘Alascio EUROCOPTER DEUTSCHLAND GmbH

2. Adaptation Workshop > 21.06.2006 Folie 2 > TAU Adaptation on EC145 > Britta Schöning Introduction Geometries EC145 and BK117-C2 Grid generation Calculation parameters CFD results Forces and moments (FLOWer/TAU/Experiment) Pressure and skin friction lines (FLOWer/TAU) TAU adaptation Conclusion Overview

3. Adaptation Workshop > 21.06.2006 Folie 3 > TAU Adaptation on EC145 > Britta Schöning Introduction Background and Objective Unsteady RANS equations have reached a high degree of accuracy for moderate detached flows (like on airplanes). Objective of the work was to investigate the effect of turbulence models in high separation areas on particularly complex helicopter fuselage such as the EC145 investigation of TAU adaptation capability comparison FLOWer / TAU The blunt body of the EC145 helicopter is caused by its missions. Because of the high curvature in the area of the back door we can expect massive separations for which aerodynamic simulation tools are necessary.

4. Adaptation Workshop > 21.06.2006 Folie 4 > TAU Adaptation on EC145 > Britta Schöning CAD modelCFD model CATIA V4 Simplifying the geometry Repairing the surface patches Closing of air intakes and jet exhausts Geometry CFD model: EC145 CAD model

5. Adaptation Workshop > 21.06.2006 Folie 5 > TAU Adaptation on EC145 > Britta Schöning stabilizers back door area EC145 BK117-C2 conical junction air inlets - cabin roof Geometries Comparison: EC145 (CFD model) BK117-C2 (experimental model)

6. Adaptation Workshop > 21.06.2006 Folie 6 > TAU Adaptation on EC145 > Britta Schöning 88697 surface points 25 prism layers (without chopping) 3.7  10 6 points pre-refined mesh Grid Generation Hybrid Grid Generation by Centaur TAU

7. Adaptation Workshop > 21.06.2006 Folie 7 > TAU Adaptation on EC145 > Britta Schöning Volume grid C-O topology 64 blocks 80968 surface points 4.9 Mio. points FLOWer Grid generation Structured Grid Generation by ICEM Hexa

8. Adaptation Workshop > 21.06.2006 Folie 8 > TAU Adaptation on EC145 > Britta Schöning M = 0.117 α = -18°, -12°, -6°, 0°, +6°, +12° Re = 2.7·10 6 Multi-grid: 3v cycle Steady calculation on Linux-Cluster (16 processors) FLOWerTAU Turbulence models 2-equation model SST by Menter 7-equation model RSM 2-equation model Wilcox k-  2-equation model SST by Menter CFD Code DLR TAU/FLOWer Finite Volume Solver for 3D RANS Equations

9. Adaptation Workshop > 21.06.2006 Folie 9 > TAU Adaptation on EC145 > Britta Schöning Drag coefficient Lift coefficient Pitching moment CFD results Forces and Moments BK117-C2 Experiment FLOWer: RSM FLOWer: SST k-ω TAU: Wilcox k-ω TAU: SST k-ω  [  ] TAU: SST k-ω 2. adaptation cLcL cmcm cDcD

10. Adaptation Workshop > 21.06.2006 Folie 10 > TAU Adaptation on EC145 > Britta Schöning CFD Results Skin Friction Lines 2-equation SST k- ω turbulence model 7-equation RSM turbulence model FLOWer 2-equation SST k- ω turbulence model 2-equation Wilcox k- ω turbulence model TAU

11. Adaptation Workshop > 21.06.2006 Folie 11 > TAU Adaptation on EC145 > Britta Schöning CFD Results Pressure Coefficient Cut plane y = 0 [mm]

12. Adaptation Workshop > 21.06.2006 Folie 12 > TAU Adaptation on EC145 > Britta Schöning FLOWer – RSM model FLOWer – SST k-ω model TAU – SST k-ω model TAU – Wilcox k-ω model CFD Results Total Pressure Losses Cut plane y = 0 α = 0°

13. Adaptation Workshop > 21.06.2006 Folie 13 > TAU Adaptation on EC145 > Britta Schöning 3.7  10 6 points Total Pressure Losses α = 0° 4.9  10 6 points TAU without adaptation CFD Results Prediction of Wake

14. Adaptation Workshop > 21.06.2006 Folie 14 > TAU Adaptation on EC145 > Britta Schöning TAU Adaptation (1) Pre-refined mesh: sufficient to predict total forces and moments Goal: TAU adaptation to improve local field phenomena and interaction with tail Adaptation variable: Total pressure losses Two adaptation steps Number of points: start grid 3.7Mio points grid of 1st adaptation 4.3Mio points (+16%) grid of 2nd adaptation 5.1Mio points (+18%) Additional parameters: - minimum edge length - no cut out boxes - 2nd adaptation with re- and de-refinement approach Adaptation of the SST turbulence model results

15. Adaptation Workshop > 21.06.2006 Folie 15 > TAU Adaptation on EC145 > Britta Schöning TAU Adaptation (2) Start grid 1. adaptation 2. adaptation

16. Adaptation Workshop > 21.06.2006 Folie 16 > TAU Adaptation on EC145 > Britta Schöning Calculation on initial grid Calculation on 1. adaptation Calculation on 2. adaptation TAU Adaptation (3) Wake, total pressure losses, y = 0, α = 0° border of pre-refinement

17. Adaptation Workshop > 21.06.2006 Folie 17 > TAU Adaptation on EC145 > Britta Schöning CFD Results Pressure Coefficient Cut plane y = 0 [mm]

18. Adaptation Workshop > 21.06.2006 Folie 18 > TAU Adaptation on EC145 > Britta Schöning TAU Adaptation (4) Wake, total pressure losses, α = 0° Calculation on initial grid Calculation on 2. adaptation

19. Adaptation Workshop > 21.06.2006 Folie 19 > TAU Adaptation on EC145 > Britta Schöning The comparison of forces and moments between the solvers FLOWer and TAU and the experimental data show a good agreement without TAU adaptation but with a pre-refined grid. TAU adaptation improves resolution of local flow phenomena, necessary to be compatible with structured meshes (FLOWer). Future plans: Further work planned in SHANEL to qualify adaptation capability for helicopter applications (BVI, helicopter wakes). Conclusion, Outlook