In the framework of the AIM project the near field of the blade tip vortex of a full-scale helicopter in simulated hover flight was investigated by combining three-component Particle Image Velocimetry and Background Oriented Schlieren measurements. The velocity field measurements in the range of wake ages of ψ v = 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\uppsi _{\mathrm{{v}}}={1}^\circ }$$\end{document} to 30 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${30}^\circ $$\end{document} in azimuth provided a reference for a quantitative analysis of the Schlieren results yielding vortex core density estimates. Ongoing vortex roll-up was observed at ψ v = 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\uppsi _{\mathrm{{v}}}={1}^\circ }$$\end{document} while considerable aperiodicity was persistent thereafter. The vortex parameters for ψ v > 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\uppsi _{\mathrm{{v}}}>{1}^\circ }$$\end{document} were consistent with the Scully vortex model. The particular challenges of full-scale, outdoor testing, especially the limited spatial resolution and aperiodicity effects, resulted in elevated measurement uncertainty as compared to sub-scale experiments.


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    Title :

    Towards In-Flight Measurements of Helicopter Blade Tip Vortices


    Additional title:

    Research Topics in Aerospace


    Contributors:


    Publication date :

    2013-02-14


    Size :

    15 pages





    Type of media :

    Article/Chapter (Book)


    Type of material :

    Electronic Resource


    Language :

    English




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    Towards Density Reconstruction of Helicopter Blade Tip Vortices from High-Speed Background-Oriented Schlieren Data

    Braukmann, J. N. / Bauknecht, A. / Wolf, C. C. et al. | British Library Conference Proceedings | 2018