Transition mechanisms in hypersonic wind-tunnel nozzles: a methodological approach using global linear stability analysis

Fuente: arXiv
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Main Authors: Lemarquand, Hugo, Lugrin, Mathieu, Content, Cédric, Caillaud, Clément, Esquieu, Sébastien, Sipp, Denis
Format: Preprint
Published: 2025
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_version_ 1866913805823377408
author Lemarquand, Hugo
Lugrin, Mathieu
Content, Cédric
Caillaud, Clément
Esquieu, Sébastien
Sipp, Denis
author_facet Lemarquand, Hugo
Lugrin, Mathieu
Content, Cédric
Caillaud, Clément
Esquieu, Sébastien
Sipp, Denis
contents Base-flow computations and stability analyses are performed for a hypersonic wind tunnel nozzle at a Mach number of 6. Isothermal and adiabatic wall boundary conditions are investigated, and moderate stagnation conditions are used to provide representative scenarios to study the transition in quiet hypersonic wind tunnel facilities. Under these conditions, the studied nozzle shows a small flow separation at the convergent inlet. Global stability analysis reveals that this recirculation bubble may trigger a classical three-dimensional stationary unstable global mode. Resolvent analysis reveals Görtler, first and second Mack modes affecting the divergent part of the nozzle, along with a Kelvin-Helmholtz instability induced by the bubble. The present study also highlights the key impact of perturbations located in the convergent inlet on the development of instabilities further downstream in the divergent outlet, helping understand the need and efficacy of a suction lip upstream of the nozzle throat to mitigate instabilities in the divergent nozzle. Detailed knowledge of all these mechanisms is essential for understanding flows in quiet hypersonic wind tunnel nozzles and, consequently, represents a key step toward the optimisation of such nozzles.
format Preprint
id arxiv_https___arxiv_org_abs_2504_16679
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Transition mechanisms in hypersonic wind-tunnel nozzles: a methodological approach using global linear stability analysis
Lemarquand, Hugo
Lugrin, Mathieu
Content, Cédric
Caillaud, Clément
Esquieu, Sébastien
Sipp, Denis
Fluid Dynamics
Base-flow computations and stability analyses are performed for a hypersonic wind tunnel nozzle at a Mach number of 6. Isothermal and adiabatic wall boundary conditions are investigated, and moderate stagnation conditions are used to provide representative scenarios to study the transition in quiet hypersonic wind tunnel facilities. Under these conditions, the studied nozzle shows a small flow separation at the convergent inlet. Global stability analysis reveals that this recirculation bubble may trigger a classical three-dimensional stationary unstable global mode. Resolvent analysis reveals Görtler, first and second Mack modes affecting the divergent part of the nozzle, along with a Kelvin-Helmholtz instability induced by the bubble. The present study also highlights the key impact of perturbations located in the convergent inlet on the development of instabilities further downstream in the divergent outlet, helping understand the need and efficacy of a suction lip upstream of the nozzle throat to mitigate instabilities in the divergent nozzle. Detailed knowledge of all these mechanisms is essential for understanding flows in quiet hypersonic wind tunnel nozzles and, consequently, represents a key step toward the optimisation of such nozzles.
title Transition mechanisms in hypersonic wind-tunnel nozzles: a methodological approach using global linear stability analysis
topic Fluid Dynamics
url https://arxiv.org/abs/2504.16679