A localized heating or cooling effect on stability of the boundary-layer flow on a sharp cone at zero angle of attack and freestream Mach number 6 is analyzed. Experiments were carried out in the Transit-M wind tunnel of the Institute of Theoretical and Applied Mechanics (Novosibirsk, Russia) for different heating/cooling intensities and freestream Reynolds numbers. The mean flows with localized heating/cooling are calculated using axisymmetric Navier-Stokes equations. These solutions are used for the spatial linear stability analysis to estimate the transition onset points using the e N method. Direct numerical simulations of two-dimensional disturbances propagating in the boundary layer through the cooled/heated region are performed. The experiment and computations showed similar qualitative trends. The localized cooling decreases the second-mode amplitude and delays transition. The heating produced an opposite effect, which is less pronounced.

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Hypersonic boundary layer stability and transition were studied experimentally and numerically for the test case of 7 degree half-angle cone equipped with local wall heating and cooling. The experiments were performed for M = 6. Heat §ux distributions and wall pressure pulsations were measured. It was obtained that variation of the wall temperature signi¦cantly a¨ects the transition location. It was found that development of the second mode depends on the upstream wall temperature. The results of numerical simulation con¦rmed the general trends of the second mode evolution obtained in the experiment.