Please use this identifier to cite or link to this item:
http://hdl.handle.net/10397/92723
Title: | Transition to turbulence in hypersonic flow over a compression ramp due to intrinsic instability | Authors: | Cao, S Hao, J Klioutchnikov, I Wen, CY Olivier, H Heufer, KA |
Issue Date: | 25-Jun-2022 | Source: | Journal of fluid mechanics, 25 June 2022, v. 941, A8 | Abstract: | In this work, a transition process in a hypersonic flow over a cold-wall compression ramp is studied using direct numerical simulation (DNS) and global stability analysis (GSA). The free-stream Mach number and the Reynolds number based on the flat-plate length are 7.7 and 8.6 x 10(5), respectively. The shock-induced pressure rise causes the boundary layer to separate on the flat plate, forming a separation bubble around the corner. Without introducing any external disturbances, the DNS captures the transition to turbulence downstream of flow reattachment. The DNS results agree well with the experimental data as well as theoretical predictions. To uncover the intrinsic instability in the flow system, GSA is employed to investigate the three-dimensionality of the two-dimensional base flow. Several stationary and oscillatory unstable modes are revealed, which result in spanwise periodicity inside and downstream of the separation bubble. The GSA and DNS results indicate that the intrinsic instability of the flow system triggers the formation of streamwise counter-rotating vortices and boundary-layer streaks near reattachment. The downstream transition to turbulence starts from the breakdown of the streamwise vortices and streaks. Moreover, the second harmonic of the most unstable global mode and a broadband low-frequency unsteadiness occur in the saturated flow, which has a significant influence on the transition process. In summary, the present study demonstrates a transition process in a hypersonic compression-ramp flow as a result of the intrinsic instability of the flow system. | Keywords: | Boundary layer separation Shock waves Transition to turbulence |
Publisher: | Cambridge University Press | Journal: | Journal of fluid mechanics | ISSN: | 0022-1120 | EISSN: | 1469-7645 | DOI: | 10.1017/jfm.2022.277 | Rights: | © The Author(s), 2022. Published by Cambridge University Press. This is an Open Access article,
distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.
org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium,
provided the original work is properly cited. The following publication Cao, S., Hao, J., Klioutchnikov, I., Wen, C. Y., Olivier, H., & Heufer, K. A. (2022). Transition to turbulence in hypersonic flow over a compression ramp due to intrinsic instability. Journal of Fluid Mechanics, 941, A8 is available at https://doi.org/10.1017/jfm.2022.277 |
Appears in Collections: | Journal/Magazine Article |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
transition-to-turbulence-in-hypersonic-flow-over-a-compression-ramp-due-to-intrinsic-instability.pdf | 3.52 MB | Adobe PDF | View/Open |
Page views
63
Last Week
1
1
Last month
Citations as of May 5, 2024
Downloads
36
Citations as of May 5, 2024
SCOPUSTM
Citations
12
Citations as of Apr 19, 2024
WEB OF SCIENCETM
Citations
15
Citations as of May 2, 2024
Google ScholarTM
Check
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.