| Autor: |
Lugrin, Mathieu, Beneddine, Samir, Leclercq, Colin, Garnier, Eric, Bur, Reynald |
| Rok vydání: |
2020 |
| Předmět: |
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| Zdroj: |
J. Fluid Mech. 907 (2021) A6 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1017/jfm.2020.833 |
| Popis: |
A high-fidelity simulation of the shock/transitional boundary layer interaction caused by a 15-degrees axisymmetrical compression ramp is performed at a freestream Mach number of 5 and a transitional Reynolds number. The inlet of the computational domain is perturbed with a white noise in order to excite convective instabilities. Coherent structures are extracted using Spectral Proper Orthogonal Decomposition (SPOD), which gives a mathematically optimal decomposition of spatio-temporally correlated structures within the flow. The mean flow is used to perform a resolvent analysis in order to study non-normal linear amplification mechanisms. The comparison between the resolvent analysis and the SPOD results provides insight on both the linear and non-linear mechanisms at play in the flow. To carry out the analysis, the flow is separated into three main regions of interest: the attached boundary layer, the mixing layer and the reattachment region. The observed transition process is dependent on the linear amplification of oblique modes in the boundary layer over a broad range of frequencies. These modes interact nonlinearly to create elongated streamwise structures which are then amplified by a linear mechanism in the rest of the domain until they break down in the reattachment region. The early nonlinear interaction is found to be essential for the transition process. |
| Databáze: |
arXiv |
| Externí odkaz: |
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