Experimental Study of the Laminar-Turbulent Transition on a Blunt Cone
E. A. Aleksandrova1,2, A. V. Novikov1,2, S. V. Utyuzhnikov2,3, A. V. Fedorov1,2
1Joukowski Central Aerohydrodynamic Institute, Zhukovskii, 140180 Russia
2Moscow Institute of Physics and Technology, Dolgoprudnyi, 141700 Russia
3The University of Manchester, M13 9PL Manchester, UK
Keywords: Laminar-turbulent transition, hypersonic flows, blunt cone, reverse of the laminar-turbulent transition, "blunt body paradox", experiment
Abstract
Results of an experimental study of the laminar-turbulent transition in a hypersonic flow around cones with different bluntness radii at a zero angle of attack, free-stream Mach number M∞ = 6, and unit Reynolds number in the interval Re∞, 1 = 5.79 · 1065.66 · 107 m-1 are presented. Flow regimes in which a reverse of the laminar-turbulent transition (decrease in the length of the laminar segment with increasing bluntness radius) are studied. Heat flux distributions over the model surface are obtained with the use of temperature-sensitive paints. Lines of the beginning of the transition in the boundary layer are analyzed by using heat flux fields. The critical Reynolds number Re∞, R ≈ 1.3 · 105 beginning from which the laminar-turbulent transition substantially depends on uncontrolled disturbances, such as the model tip roughness, is found. In supercritical regimes, the line of the transition beginning is shifted in most cases toward the model tip (reverse of the transition). The results obtained are compared with available experimental data.
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