An evaluation is made of extensive three-component (3-C) particle image velocimetry (PIV) measurements within the wake across a rotor disk plane. The model is a 40 percent scale BO-105 helicopter main rotor in forward flight simulation. This study is part of the HART II test program conducted in the German-Dutch Wind Tunnel (DNW). Included are wake vortex field measurements over the advancing and retreating sides of the rotor operating at a typical descent landing condition important for impulsive blade-vortex interaction (BVI) noise. Also included are advancing side results for rotor angle variations from climb to steep descent. Using detailed PIV vector maps of the vortex fields, methods of extracting key vortex parameters are examined and a new method was developed and evaluated. An objective processing method, involving a center-of-vorticity criterion and a vorticity “disk” integration, was used to determine vortex core size, strength, core velocity distribution characteristics, and unsteadiness. These parameters are mapped over the rotor disk and offer unique physical insight for these parameters of importance for rotor noise and vibration prediction.
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References
1.
SchmitzF. H., “Rotor Noise”, Aeroacoustics of Flight Vehicles, Theory and Practice, Vol. 1, Noise Sources, edited by HubbardH. H., Acoustical Society of America, New York, 1995, pp. 65–149.
2.
BoxwellD. aSchmitzF. H.SplettstoesserW. R.SchultzK. J., “Helicopter Model Rotor-Blade Vortex Interaction Impulsive Noise: Scalablity and Prarmetric Variations,”Journal of American Helicopter Society, vol. 32, No. 1, 1987.
3.
BrooksT.F.BoothE.R.SplettstoesserW. R.SchultzK. J.KubeR.NieselG., and StrebyO., “Analysis of a Higher Harmonic Control Test to Reduce Blade Vortex Interaction Noise,”Journal of Aircraft, Vol. 31, No. 6, Nov-Dec 1994, pp. 1341–1349.
4.
SplettstoesserW. R.SchultzK. J.KubeR.BrooksT. F.BoothE. R.NieselG., and StrebyO., “BVI Impulsive Noise Reduction by Higher Harmonic Pitch Control: Results of a Scaled Model Rotor Experiment in the DNW,” presented at the 17th European Rotorcraft Forum, September 24–26, 1991, Berlin, Germany.
5.
BrooksT. F.BurleyC. L., “Rotor Broadband Noise Prediction with Comparison to Model Data,”, AIAA Paper 01–2210, 7th AIAA/CEAS Aeroacoustics Conference, Maastricht, The Netherlands, May 2001.
6.
BrezillonJ.PrieurJ., and RahierG., “Investigation on Broadband Helicopter Rotor Noise,”AHS Technical Specialists' Meeting For Rotorcraft Acoustics and Aerodynamics, Williamsburg, Virginia, October 28–30, 1997.
7.
YuY. H.GmelinB.HellerH.PhilippeJ. J.MerckerE., and PreisserJ. S., “HHC Aeroacoustics Rotor Test at the DNW – the Joint German/French/US HART project,” 20th European Rotorcraft Forum, Amsterdam, Netherlands, 1994.
8.
KubeR.SplettstoesserW. R.WagnerW.SeelhorstU.YuY. H.BoutierA.PrieurJ., and MerckerE., “Initial Results from the Higher Harmonic Control Aeroacoustic Rotor Test (HART) in the German-Dutch Wind Tunnel,” presented at the 75th AGARD Fluid Dynamics Panel Symposium on Aerodynamics and Acoustics of Rotorcraft, Berlin, Germany, 10–14 October 1994.
9.
SplettstoesserW. R.KubeR.WagnerW.SeelhortsU.BoutierA.MicheliF.MerckerE.PengelK., “Key Results from a Higher Harmonic Control Aeroacoustic Rotor Test (HART),”Journal of the American Helicopter Society, January 1997.
10.
MerckerE.PengelK., “Flow Visualization of Helicopter Blade-Tip Vortices – a qualitative Technique to Determine the Trajectory and the Position of the Tip Vortex Pattern of a Model Rotor,” 18th European Rotorcraft Forum, Avignon, France, 1992.
11.
SeelhorstU.ButefischK. A.SauerlandK. H., “Three Component Laser-Doppler Velocimeter Development for Large Wind Tunnel, ICIASF, 1993 Record, 1993.
12.
GallmanJ. M.TungC.SchultzK.-J.SplettstoesserW.BuchholzH.SpiegelP.BurleyC. L.BrooksT. F., and BoydD. D.Jr., “Effect of Wake Structure on Blade-Vortex Interaction Phenomena: Acoustic Prediction and Validation,” 16th AIAA Aeroacoustic Conference, Munich, Germany, June 1995.
13.
TungC.GallmanJ. M.KubeR.WagnerW.Van der WallB.BrooksT. F.BurleyC. L.BoydD. D.RahierG., and BeaumierP., “Prediction and Measurement of Blade-Vortex Interaction Loading,” presented at the 1st Joint CEAS/AIAA Aeroacoustics Conference, Munich, Germany, June 12–15, 1995.
14.
BrooksT. F.BoydD. D.BurleyC. L., and JollyR. J., “Aeroacoustic Codes for Rotor Harmonic and BVI Noise-CAMRAD. Mod1/HIRES,”Journal of the American Helicopter Society, pp. 63–79, Apr. 2000.
15.
CostesM.BeaumierP.BettschartN.CoppensG., and ServeraG., “Computational Tools Used At ONERA for the Description of Helicopter Rotor Wakes,” AIAA Paper 00–0113, 38th Aerospace Sciences Meeting and Exhibit, Reno, NV 2000.
16.
LimJ.W.TungC., and YuY.H., “Prediction of Blade-Vortex Interaction Airloads with Higher-Harmonic Pitch Controls Using the 2GCHAS Comprehensive Code,”Journal of Pressure Vessel Technology, Transaction of the ASME, Vol. 123, No. 4, 2001.
17.
WachspressD. A.QuackenbushT. R., “BVI Noise Prediction Using a Compreshensive Rotorcraft Analysis,”American Helicopter Society 57th Annual Forum, Washington, D. C., May 9–11, 2001.
18.
van der WallB. G., “Vortex Characteristics Analysed From HART Data”, European Rotorcraft Forum, Dresden, Germany, 1997.
19.
KubeR., and SchultzK. J., “Vibration and BVI Noise Reduction by Active Rotor Control: HHC Compared to IBC.” 22nd European Rotorcraft Forum, Brighton, UK, 1996.
20.
LeishmanJ. G.BakerA., and CoyneA. J., “Measurements of Rotor Tip Vorticies Using Three-Component Laser Doppler Velocimetry, Journal of the American Helicopter Society, Vol. 41, No. 4, 1996.
21.
LeishmanJ. G., “Measurements of the Aperiodic Wake of a Hovering Rotor,”Experiments in Fluids, vol. 25, No. 4, 1998, pp. 352–361.
22.
HanY. O.LeishmanJ. G., and CoyneA. J., “Measurement of the Velocity and Turbulence Structure of a Rotor Tip Vortex,”AIAA Journal, Vol. 35, No. 3, March 1997.
23.
CoyneA. J.GhagwatM. J.LeishmanJ. G., “Investigation into the Rollup and Diffusion of Rotor Tip Vortices Using Laser Doppler Velocimetry,” 53rd Annual American Helicopter Society Forum, May 1997.
24.
BhagwatM. J.LeishmanJ. G., “Generalized Viscous Vortex Model for Application to Free-Vortex Wake and Aeroacoustic Calculations,” American Helicopter Society 58th Annual Forum, Montreal, Canada, June 11–13, 2002.
25.
BhagwatM. J.LeishmanJ. G., “Correlation of Helicopter Rotor Tip Vortex Measurements,”AIAA Journal, Vol. 38, No. 2, 2000, pp. 301–308.
26.
MartinP. B.PuglieseG. J., and LeishmanJ. G., “High Resolution Trailing Vortex Measurements in the Wake of a Hovering Rotor,”American Helicopter Society 57th Annual Forum, Washington, D.C., May 9–11, 2001.
27.
MartinP. B.LeishmanJ. G., “Trailing Vortex Measurements in the Wake of A Hovering Rotor Blade with Various Tip Shapes,” American Helicopter Society 58th Annual Forum, Montreal, Canada, June 11–13, 2002.
28.
HeineckJ. T.YamauchiG. K.WadcockA. J.LourencoL., and AbregoA. I., “Application of Three-Component PIV to a Hovering Rotor Wake,” American Helicopter Society 56th Annual Forum, Virginia Beach, Virginia, May 2–4, 2000.
29.
McAlisterK. W.TungC., and HeineckJ. T., “Forced Diffusion of Trailing Vorticity From a Hovering Rotor,”American Helicopter Society 57th Annual Forum, Washington, D.C., May 9–11, 2001.
30.
RaffelM.SeelhorstU., and WillertC., “Vortical Flow Structures at a Helicopter Rotor Model Measured by LDV and PIV,”The Aeronautical Journal, Paper No. 2227, April 1998.
31.
MurashigeA.TsuchihashiA.TsujiuchiT., and YamakawaE., “Blade-tip vortex Measurement by PIV, Proc of the 23rd European Rotorcraft Forum, Paper 36, Dresden, Germany, 1997.
32.
YamauchiG. K.BurleyC. L.MerckerE.PengelK., and JanakiRamR., “Flow Measurements of an Isolated Model Tilt Rotor,”American Helicopter Society 55th Annual Forum, Montreal, Canada, May 25–27, 1999.
33.
YuY. H.TungC.van der WallB. G.PausderJ.BurleyC. L.BrooksT. F.BeaumierP.DelrieuxY.MerckerE., and PengelK., “The HART-II Test: Rotor Wakes and Aeroacoustics with Higher-Harmonic Pitch Control (HHC) Inputs – The Joint German/French/Dutch/US Project”, American Helicopter Society 58th Annual Forum, Montreal, Canada, May 25–27, 2002.
34.
RaffelM.RichardH.SchneiderG.KlingeF.EhrenfriedK.PengelK., and GeenstraG., “Recording and Evaluation Methods of PIV Investigations on a Helicopter Rotor Model,” 11th International Symposium on Applications of Laser Techniques to Fluid Mechanics, Lisbon, 8–11 July, 2002.
35.
RichardH.RaffelM., “Rotor Wake Measurements: Full-scale and Model Tests,”American Helicopter Society 58th Annual Forum, Montreal, Canada, May 25–27, 2002.
36.
van der WallB. G.JunkerB.BurleyC. L.BrooksT. F.YuY.TungC.RaffelM.HuguesR.WagnerW.MerckerE.PengeK.HolthusenH.BeaumierP., and DelrieuxY., “The HART II Test in the LLF of the DNW – A Major Step Towards Rotor Wake Understanding,”28th European Rotorcraft Forum, Bristol, England, September, 17–20, 2002.
RaffelM.WillertC.KompenhansJ., Particle Image Velocimetry, A practical Guide, Springer, ISBN 3-540-63683-8, 1998.
39.
VatistasG. H.KozelV.MihW. C., “A Simpler Model For Concentrated Vortices,”Experiments in Fluids, vol. 11, 1991.
40.
ScullyM. P., “Computation of Helicopter Rotor Wake Geometry and Its Influence on Rotor Harmonic Airloads,”Massachusetts Institute of Technology, ASRL TR 178–1, Mar. 1975.
