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Innovative Scientific Solutions Inc. Air Force Research Lab

Innovative Scientific Solutions Inc. Air Force Research Lab. Simultaneous Measurements of Pressure and Deformation on a UCAV in the SARL. J. Crafton, S. Fonov, E. Jones, L. Goss V. Fonov Innovative Scientific Solutions Inc. C. Tyler Air Force Research Lab. Motivation: Shorten Design Cycle.

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Innovative Scientific Solutions Inc. Air Force Research Lab

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  1. Innovative Scientific Solutions Inc.Air Force Research Lab

  2. Simultaneous Measurements of Pressure and Deformation on a UCAV in the SARL J. Crafton, S. Fonov, E. Jones, L. Goss V. Fonov Innovative Scientific Solutions Inc. C. Tyler Air Force Research Lab

  3. Motivation: Shorten Design Cycle Model Design Numerical Prediction Rapid Prototype Build Model Pressure, Velocity, Skin Friction, Geometry Experimental Data Compare CFD & EFD AIAA-0035 AIAA-0440 AIAA-1028 Validate Numerical Code

  4. Pressure-Sensitive Paint

  5. Sensitivity to pressure • 5% per [psi] • Sensitivity to temperature • 0.5% per [K] • Ideal paint • temperature sensitivity independent of pressure

  6. Uncertainty in PSP Measurements (Liu) • Model parameters • Temperature • Illumination (model movement & lamp stability) • Calibration • Photo-degradation & Sedimentation • Spectral content of excitation • Filter leakage • Sensitivity coefficients • Compute sensitivity and identify major sources • Temperature • Illumination

  7. Probe 1  L1(T,P,I)  signal Probe 2  L2(T,P,I)  reference Illumination • Model movement/deformation • Lamp stability • Binary PSP • reference probe • Luminescence • Linear function of illumination • Ratio signal/reference

  8. jet • Inclined Impinging Jet • Shocks, Expansions, Wall Jet • Cold region under jet • Recovery Temperature • Paint is not isothermal • Common in PSP experiments

  9. Probe 1  L1(T,P,I)  signal Probe 2  L2(T,P,I)  reference Temperature • Temperature • model construction • metal  isothermal • plastic/ceramic  adiabatic • temperature changes all day • recovery temperature • Binary PSP • Use reference probe for temperature correction • Reference probe • Match temperature sensitivity of PSP • Ideal paint is very valuable here (FIB)

  10. Binary FIB Paint • Temperature sensitivity • ~ 25 times less than FIB • Uncertainty • 50 Pa/K

  11. Signal Channel -vs- Binary M = 0.4  = 20  0.4 psi 14 • Illumination error - 30% of scale - model displacement 12 psi

  12. Low Speed PSP • System approach • Binary paint with very little temperature sensitivity • Stable illumination source (spectral content essential) • Single camera and filter switch • Average!!! • Post run Wind-off (capture any thermal profile) • Process on the mesh if you can (I recommend Sergey) • Model • Stiff model and mount (no movement if possible) • Isothermal materials • Tunnel • Open circuit tunnel (minimize temperature) • Dark and be consistent

  13. 1/24th Scale Car at 50 m/s AFIT Tunnel Binary FIB Data acquisition ~ 12 sec

  14. Flow Low Speed PSP V=17 m/s NASA Ames (Dr. J. Bell) Binary FIB p (psi) 0.05 taps reference targets -0.4

  15. UCAV Flow • 5 PDV data planes near wing/body junction • Mach 0.2 • free stream ~ 68 m/s • 20 angle of attack

  16. UCAV in SARL Vortex from nose

  17. UCAV in SARL Vortex from nose Breaking down Vortex from wing Body junction

  18. UCAV in SARL

  19. UCAV in SARL

  20. UCAV Results • compare PSP to taps • sigma  0.16 psi  demonstrated 0.005 psi • background noise • background • 7:00 AM  1000 • 12:00 AM  30000 • dynamic background • cloud noise? • shorten exposure time • more lamps • more interlaced backgrounds M = 0.4  = 20  = 0.16 psi

  21. Model Deformation • Stereo view of the model • signal and reference camera • Markers with known positions • pressure taps or resection markers • Photogrammetry (Stereo PIV) • wind-on marker positions on bitmap • reconstruct physical location of each marker • yields 3 components of deformation • Binary PSP Stereo & Photogrammetry System • minimal impact on test • increase value  pressure and geometry

  22. Stereo Photogrammetry System • Calibration • wind-off markers • need a 3D field • Dynamic range • camera depth of field • Accuracy (Stereo PIV) • ~ 1/10 pixel in plane • ~ 1 pixel out of plane • Response time • Limited by camera

  23. Model Deformation • Root to Tip deformation - d 0.4 in • Bulk displacement -  1.0 in • Improve spatial resolution - more markers - non-uniform paint • Improve frequency response - faster camera (limited) M = 0.4  = 20

  24. Conclusions and Future Work • Demonstrated measurements of Pressure & Deformation • Developed integrated system using binary PSP hardware • Binary PSP • minimize errors due to illumination and temperature • extending PSP to lower speeds • Stereo Photogrammetry • utilized binary PSP images for displacement measurements • determined 3 components of model displacement • Future Work • Feed deformed geometry back to CFD • Tools for quick comparison of EFD/CFD

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