To address the hitherto unknown mechanism of boundary-layer transition on blunt reentry capsules, the role of roughness-induced disturbance growth on a spherical-section forebody is assessed via optimal transient growth theory and direct numerical simulations (DNS). Optimal transient-growth studies have been performed for the blunt capsule experiments at Mach 5.9 in the Hypersonic Ludwieg tube at the Technische Universität Braunschweig (HLB), which included measurements behind a patch of controlled, distributed micron-sized surface roughness. Transient-growth results for the HLB capsule indicate similar trends as the corresponding numerical data for a Mach 6 experiment in the Actively Controlled Expansion (ACE) facility of the Texas A&M University (TAMU) at a lower Reynolds number. Both configurations indicate a similar dependence on surface temperature ratio and, more important, rather low values of maximum energy gain. DNS are performed for the conditions of the HLB experiment to understand the generation of stationary disturbances by the roughness patch and the accompanying evolution of unsteady perturbations. However, no evidence of either modal or nonmodal disturbance growth in the wake of the roughness patch is found in the DNS data; thus, the physical mechanism underlying the observed onset of transition still remains unknown.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen


    Exportieren, teilen und zitieren



    Titel :

    Numerical Investigation of Roughness Effects on Transition on Spherical Capsules


    Beteiligte:
    Stefan Hein (Autor:in) / Alexander Theiss (Autor:in) / Antonio Di Giovanni (Autor:in) / Christian Stemmer (Autor:in) / Thomas Schilden (Autor:in) / Wolfgang Schröder (Autor:in) / Pedro Paredes (Autor:in) / Meelan M Choudhari (Autor:in) / Fei Li (Autor:in) / Eli Reshotko (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    2019-01-29




    Medientyp :

    Sonstige


    Format :

    Keine Angabe


    Sprache :

    Englisch


    Schlagwörter :


    Numerical Investigation of Roughness Effects on Transition on Spherical Capsules

    Hein, Stefan J. / Theiss, Alexander / Di Giovanni, Antonio et al. | AIAA | 2018


    Numerical Investigation of Roughness Effects on Transition on Spherical Capsules

    Hein, Stefan / Theiss, Alexander / Di Giovanni, Antonio et al. | AIAA | 2019


    Numerical Investigation of Roughness Effects on Transition on Spherical Capsules (AIAA 2018-0058)

    Hein, Stefan J. / Theiss, Alexander / Di Giovanni, Antonio et al. | British Library Conference Proceedings | 2018


    Experimental Investigation of Roughness Effects on Transition on Blunt Spherical Capsule Shapes

    Radespiel, Rolf / Ali, Syed R. C. / Muñoz, Federico et al. | AIAA | 2018