Experimental analysis of transition delay by means of roughness elements

Abstract : An experimental activity aimed at the development of a passive method for viscous drag reduction in an aerodynamic body is presented. The reduction is achieved by delaying the laminar-turbulent transition of the boundary layer. The research is motivated by previous linear stability analysis where it was demonstrated that stable streaks in a boundary layer are capable to stabilize the growth of Tollmien-Schlichting waves. In this paper the results of a series of experiments on a flat plate are presented. Firstly, it is shown that by means of suitable roughness elements it is possible to generate stable steady streaks of amplitudes up to 12% of the free stream velocity. Secondly, it is demonstrated that the generated streaks are really effective in reducing the growth of the Tollmien-Schlichting waves as predicted by the theory. Finally, it is shown that using this passive control technique it is possible to sensibly delay transition to turbulence.
Type de document :
Communication dans un congrès
36th AIAA Fluid Dynamics Conference, Jun 2006, San Francisco, United States. 2, pp.1464-1478, 2006
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https://hal-polytechnique.archives-ouvertes.fr/hal-01026021
Contributeur : Denis Roura <>
Soumis le : lundi 21 juillet 2014 - 13:34:11
Dernière modification le : jeudi 11 janvier 2018 - 06:18:25

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  • HAL Id : hal-01026021, version 1

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J.H.M. Fransson, A. Talamelli, L. Brandt, Carlo Cossu. Experimental analysis of transition delay by means of roughness elements. 36th AIAA Fluid Dynamics Conference, Jun 2006, San Francisco, United States. 2, pp.1464-1478, 2006. 〈hal-01026021〉

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