Abstract When a turbulent flow reaches a sudden expansion as in the case of a backward-facing step (BFS), a turbulent separated shear layer originates from the trailing edge. The reattachment location of this shear layer varies in time and space, causing high dynamic loads on the reattachment surface. This is an inherent problem on some of today’s cryogenic space launchers, where the main engine’s nozzle suffers from high buffeting loads during the transonic phase of the ascent, due to a turbulent reattaching shear layer, especially originating from a geometric discontinuity, similar to a BFS. For this reason the aim of the current research focuses on stabilizing and reducing the reattachment length of the separated shear layer on a BFS in transonic flow by the means of passive flow control devices. Several streamwise vortex generators were examined in the Trisonic Wind Tunnel Munich (TWM) with particle image velocimetry (PIV). The investigations were conducted on a 2D model at Mach 0.8 and a Reynolds number of 1.8 × 10 5 with respect to the step height (h). The results show that streamwise vortex generators have a tremendous effect on reducing the size of the recirculation region, reducing the reattachment location by 75 % or more, when compared to the reattachment location of a BFS wake.


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    Title :

    Control of the Reattachment Length of a Transonic 2D Backward-Facing Step Flow


    Contributors:


    Publication date :

    2016-01-01


    Size :

    8 pages





    Type of media :

    Article/Chapter (Book)


    Type of material :

    Electronic Resource


    Language :

    English




    Control of the Reattachment Length of a Transonic 2D Backward-Facing Step Flow

    Bolgar, Istvan / Scharnowski, Sven / Kähler, Christian J. | British Library Conference Proceedings | 2016



    Transonic flow past a backward-facing step

    CHOW, W. L. / SHIH, T. S. | AIAA | 1977


    Effect of initial conditions on turbulent reattachment downstream ofa backward-facing step

    WESTPHAL, R. V. / StanfordUniversity, Stanford / CA, JOHNSTON et al. | AIAA | 1984