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Three-dimensional reconstruction of helicopter blade–tip vortices using a multi-camera BOS system

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Abstract

Noise and structural vibrations in rotorcraft are strongly influenced by interactions between blade–tip vortices and the structural components of a helicopter. As a result, knowing the three-dimensional location of vortices is highly desirable, especially for the case of full-scale helicopters under realistic flight conditions. In the current study, we present results from a flight test with a full-scale BO 105 in an open-pit mine. A background-oriented schlieren measurement system consisting of ten cameras with a natural background was used to visualize the vortices of the helicopter during maneuvering flight. Vortex filaments could be visualized and extracted up to a vortex age of 360°. Vortex instability effects were found for several flight conditions. For the camera calibration, an iterative approach using points on the helicopter fuselage was applied. Point correspondence between vortex curves in the evaluated images was established by means of epipolar geometry. A three-dimensional reconstruction of the main part of the vortex system was carried out for the first time using stereophotogrammetry. The reconstructed vortex system had good qualitative agreement with the result of an unsteady free-wake panel method simulation. A quantitative evaluation of the 3D vortex system was carried out, demonstrating the potential of the multi-camera background-oriented schlieren measurement technique for the analysis of blade–vortex interaction effects on rotorcraft.

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References

  • Bauknecht A, Merz CB, Raffel M (2014a) Airborne application of the background oriented Schlieren technique to a helicopter in forward flight. In: 17th int. symp. on applications of laser techniques to fluid mechanics, Lisbon, Portugal, 07–10 July, 2014

  • Bauknecht A, Merz CB, Raffel M, Landolt A, Meier AH (2014b) Blade–tip vortex detection in maneuvering flight using the background-oriented schlieren technique. J Aircraft. doi:DOIurl10.2514/1.C032672

  • Fischler MA, Bolles RC (1981) Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Commun ACM 24(6):381–395

    Article  MathSciNet  Google Scholar 

  • Hardin JC, Lamkin SL (1987) Concepts for reduction of blade/vortex interaction noise. J Aircraft 24(2):120–125

    Article  Google Scholar 

  • Hartley R, Zisserman A (2003) Multiple view geometry in computer vision. Cambridge university press, Cambridge

    Google Scholar 

  • Hartley RI (1997) In defense of the eight-point algorithm. IEEE Trans Pattern Anal Mach Intell 19(6):580–593

    Article  Google Scholar 

  • Heineck JT, Kushner LK, Schairer ET (2013) Measurements of tip vortices from a full-scale UH-60A rotor by retro-reflective background oriented schlieren and stereo photogrammetry. In: American Helicopter Society 69th Annual Forum, Phoenix, AZ, USA

  • Kindler K, Goldhahn E, Leopold F, Raffel M (2007) Recent developments in background oriented Schlieren methods for rotor blade tip vortex measurements. Exp Fluids 43:233–240. doi:10.1007/s00348-007-0328-9

    Article  Google Scholar 

  • Kindler K, Mulleners K, Richard H, van der Wall BG, Raffel M (2011) Aperiodicity in the near field of full-scale rotor blade tip vortices. Exp Fluids 50(6):1601–1610. doi:10.1007/s00348-010-1016-8

    Article  Google Scholar 

  • Klinge F, Hecklau M, Raffel M, Kompenhans J, Göhmann U (2006) Measurement of the position of rotor blade vortices generated by a helicopter in free flight by means of stereoscopic background oriented schlieren method (BOS). In: 13th intl. symp. on applications of laser techniques to fluid mechanics, Lisbon, Portugal

  • Kutz BM, Keßler M, Krämer E (2013) Experimental and numerical examination of a helicopter hovering in ground effect. CEAS Aeronaut J 4(4):397–408. doi:10.1007/s13272-013-0084-x

    Article  Google Scholar 

  • Lim JW, Strawn RC (2008) Computational modeling of HART II blade–vortex interaction loading and wake system. J Aircraft 45(3):923–933

    Article  Google Scholar 

  • Meyn LA, Bennett MS (1993) Application of a two camera video imaging system to three-dimensional vortex tracking in the 80- by 120-foot wind tunnel. In: AIAA 11th applied aerodynamics conference, Monterey, CA, USA

  • Mikhail EM, Bethel JS, McGlone JC (2001) Introduction to modern photogrammetry, vol 1. Wiley, New York

    Google Scholar 

  • Raffel M, Tung C, Richard H, Yu Y, Meier GEA (2000) Background oriented stereoscopic schlieren for full-scale helicopter vortex characterization. In: 9th int. symp. on flow visualization, Edinburgh, Scotland

  • Raffel M, Willert CE, Wereley ST, Kompenhans J (2007) Particle image velocimetry: a practical guide. Springer, Berlin

    Google Scholar 

  • Raffel M, Heineck JT, Schairer E, Leopold F, Kindler K (2014) Background-oriented schlieren imaging for full-scale and in-flight testing. J Am Helicopter Soc 59(1):1–9. doi:10.4050/JAHS.59.012002

    Article  Google Scholar 

  • Richard H, Raffel M (2001) Principle and applications of the background oriented schlieren (BOS) method. Meas Sci Technol 12(9):1576–1585. doi:10.1088/0957-0233/12/9/325

    Article  Google Scholar 

  • Splettstoesser WR, Kube R, Wagner W, Seelhorst U, Boutier A, Micheli F, Mercker E, Pengel K (1997) Key results from a higher harmonic control aeroacoustic rotor test (HART). J Am Helicopter Soc 42(1):58–78

    Article  Google Scholar 

  • Sullivan JP (1973) An experimental investigation of vortex rings and helicopter rotor wakes using a laser doppler velocimeter. Tech. rep., MIT Technical Report 183, June, 1973

  • van der Wall BG (2012) Extensions of prescribed wake modelling for helicopter rotor BVI noise investigations. CEAS Aeronaut J 3(1):93–115. doi:10.1007/s13272-012-0045-9

    Article  Google Scholar 

  • van der Wall BG, Burley CL, Yu YH, Pengel K, Beaumier P (2004) The HART II test—measurement of helicopter rotor wakes. Aerosp Sci Technol 8(4):273–284. doi:10.1016/j.ast.2004.01.001

    Article  Google Scholar 

  • Venkatakrishnan L, Meier GEA (2004) Density measurements using the background oriented schlieren technique. Exp Fluids 37:237–247. doi:10.1007/s00348-004-0807-1

    Article  Google Scholar 

  • Wadcock AJ, Yamauchi GK, Solis E, Pete AE (2011) PIV measurements in the wake of a full-scale rotor in forward flight. In: 29th AIAA applied aerodynamics conference. Honolulu, HI, USA, pp 1874–1896

  • Yin J (2012) Main rotor and tail rotor blade vortex interaction noise under the influence of the fuselage. In: 38th European rotorcraft forum, Amsterdam, The Netherlands

  • Yin J, Ahmed SR (2000) Helicopter main-rotor/tail-rotor Interaction. J Am Helicopter Soc 45:293–302

    Article  Google Scholar 

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Acknowledgments

The authors are indebted to the company Fels-Werke GmbH for providing access to the test site, the pilots U. Göhmann and S. Soffner from DLR Brunswick and other persons involved in the planning, execution, and evaluation of the flight tests, foremost M. Krebs, S. Rafati, and C. Merz.

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Authors and Affiliations

  1. Helicopter Department, Institute of Aerodynamics and Flow Technology, German Aerospace Center (DLR), Bunsenstr. 10, 37073, Göttingen, Germany

    André Bauknecht, Benjamin Ewers, Christian Wolf & Markus Raffel

  2. French-German Research Institute (ISL), 5 rue du Général Cassagnou, 68300, Saint-Louis, France

    Friedrich Leopold

  3. Helicopter Department, Institute of Aerodynamics and Flow Technology, German Aerospace Center (DLR), Lilienthalplatz 7, 38108, Braunschweig, Germany

    Jianping Yin

Authors
  1. André Bauknecht
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  2. Benjamin Ewers
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  3. Christian Wolf
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  4. Friedrich Leopold
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  5. Jianping Yin
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  6. Markus Raffel
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Correspondence to André Bauknecht.

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Bauknecht, A., Ewers, B., Wolf, C. et al. Three-dimensional reconstruction of helicopter blade–tip vortices using a multi-camera BOS system. Exp Fluids 56, 1866 (2015). https://doi.org/10.1007/s00348-014-1866-6

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  • DOI: https://doi.org/10.1007/s00348-014-1866-6

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