Numerical simulations of a transport-aircraft configuration

Goncalves, Éric; Houdeville, R.

doi:10.1080/10618560903107452

Cited by 3 publications

(1 citation statement)

References 36 publications

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“…Numerical strategy 3.1. Phoenix code All numerical simulations in this paper were run with an in-house solver named PHOENIX (Goncalves & Houdeville 2009), to compute both the linearized and the full N-S equations. The code solves the compressible N-S equations on multi-block structured grids with a finite-volume approach.…”

Section: Stability Problemmentioning

confidence: 99%

Three-dimensional instability of a flow past a sphere: Mach evolution of the regular and Hopf bifurcations

et al. 2018

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A fully three-dimensional linear stability analysis is carried out to investigate the unstable bifurcations of a compressible viscous fluid past a sphere. A time-stepper technique is used to compute both equilibrium states and leading eigenmodes. In agreement with previous studies, the numerical results reveal a regular bifurcation under the action of a steady mode and a supercritical Hopf bifurcation that causes the onset of unsteadiness but also illustrate the limitations of previous linear approaches, based on parallel and axisymmetric base flow assumptions, or weakly nonlinear theories. The evolution of the unstable bifurcations is investigated up to low-supersonic speeds. For increasing Mach numbers, the thresholds move towards higher Reynolds numbers. The unsteady fluctuations are weakened and an axisymmetrization of the base flow occurs. For a sufficiently high Reynolds number, the regular bifurcation disappears and the flow directly passes from an unsteady planar-symmetric solution to a stationary axisymmetric stable one when the Mach number is increased. A stability map is drawn by tracking the bifurcation boundaries for different Reynolds and Mach numbers. When supersonic conditions are reached, the flow becomes globally stable and switches to a noise-amplifier system. A continuous Gaussian white noise forcing is applied in front of the shock to examine the convective nature of the flow. A Fourier analysis and a dynamic mode decomposition show a modal response that recalls that of the incompressible unsteady cases. Although transition in the wake does not occur for the chosen Reynolds number and forcing amplitude, this suggests a link between subsonic and supersonic dynamics.

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Section: Stability Problemmentioning

confidence: 99%

Three-dimensional instability of a flow past a sphere: Mach evolution of the regular and Hopf bifurcations

et al. 2018

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Hybrid RANS/LES Simulation of Shock-Induced Separated Flow in Truncated Ideal Contour Nozzle

Goncalves

Lehnasch

Herpe

2019

31st International Symposium on Shock Waves 2

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Impinging shear layer instability in over-expanded nozzle dynamics

Tarsia Morisco,

Robinet,

Herpe

et al. 2023

Physics of Fluids

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When rocket engine nozzles operate at a high degree of over-expansion, an internal flow separation occurs with a strong unsteady shock–wave boundary layer interaction. The global dynamics results in a low-frequency mode, which is associated with the shock displacement, and a high-frequency mode, which is correlated with the shear layer–boundary layer interaction. While the mechanism responsible for the low-frequency oscillation is known, the one in charge of the high-frequency unsteadiness is not yet clear. The scope of this paper is to provide a physical explanation for this mechanism. To do that, a delayed detached eddy simulation is used to numerically reproduce the flow in the case of a sub-scale cold-gas truncated ideal contour nozzle. The obtained results are successfully compared to the experiments and confirm the presence of two non-axisymmetric wall pressure signatures at Strouhal numbers St=fDj/Uj≃0.2 and 0.3 with different azimuthal selections. To reveal the origin of such modes, a power spectral density analysis is performed in the separated region. The analysis shows that both modes originate from the external shear layer and behave as “twins” in the separated region. The reason is that both modes are two sides of the same impinging shear layer instability: the acoustic mode propagates with the sound velocity, while the hydrodynamic one propagates with the supersonic shear layer velocity. In this context, the resulting self-sustained dynamics may be due to an acoustic–hydrodynamic feedback loop involving the impinging shear layer instability of the external supersonic shear layer and the separated region.

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Numerical simulations of a transport-aircraft configuration

Cited by 3 publications

References 36 publications

Three-dimensional instability of a flow past a sphere: Mach evolution of the regular and Hopf bifurcations

Three-dimensional instability of a flow past a sphere: Mach evolution of the regular and Hopf bifurcations

Hybrid RANS/LES Simulation of Shock-Induced Separated Flow in Truncated Ideal Contour Nozzle

Impinging shear layer instability in over-expanded nozzle dynamics

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