Direct Simulation of Hypersonic Crossflow Instability on an Elliptic Cone

Dinzl, Derek; Candler, Graham V.

doi:10.2514/1.j055130

Cited by 54 publications

(19 citation statements)

References 30 publications

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“…Low frequency instabilities grew in between the observed streaks. DNS computations Dinzl & Candler (2017) show, for a similar flow, that increased surface heating is found in the trough between vortices and decreased heating is found at the upwelling of the vortex. This observation, paired with observations in low-speed and high-speed experiments and CFD analysis of the position of secondary instabilities, indicates that the measurements of are likely Type-I secondary instabilities.…”

Section: Crossflow Instability In High-speed Flowsmentioning

confidence: 88%

Influence of Environmental Disturbances on Hypersonic Crossflow Instability on the HIFiRE-5 Elliptic Cone

Neel

Leidy

Tichenor

et al. 2018

2018 AIAA Aerospace Sciences Meeting

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Crossflow instabilities on a 2:1 elliptic cone in hypersonic flow have been investigated in the M6QT and ACE wind tunnels at the Texas A&M National Aerothermochemistry and Hypersonics Laboratory. Experiments on a PEEK 38.1% scale model of the HIFiRE-5 flight test geometry were conducted to investigate the development of crossflow instabilities as well as to characterize the freestream and surface conditions responsible for their initial amplitudes. The freestream environment was varied not only by testing the model in both quiet and conventional tunnels but also by passively changing the fluctuation levels experienced in the conventional facility through systematic model placement. ACE freestream measurements, using a Kulite pressure transducer mounted in a pitot probe configuration and a hot-wire anemometer, indicated that fluctuation levels at the upstream model station were half those at the downstream stations. Fast-response PCB and Kulite surface mounted pressure transducers allowed examination of pressure fluctuation amplitudes and

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Section: Crossflow Instability In High-speed Flowsmentioning

confidence: 88%

Influence of Environmental Disturbances on Hypersonic Crossflow Instability on the HIFiRE-5 Elliptic Cone

Neel

Leidy

Tichenor

et al. 2018

2018 AIAA Aerospace Sciences Meeting

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“…The addition of acoustic noise caused unsteady waves to form on top of the vortices, causing their breakdown at the highest Reynolds numbers. More recent DNS simulations of Dinzl & Candler (2017) showed a difference between the centreline system of vortices and the crossflow vortices generated by surface roughness. Recent studies based on BiGlobal linear stability analysis (Paredes & Theofilis 2015;Paredes et al 2016d ) conducted on the HIFiRE-5 geometry confirmed the dominant role played by the crossflow instabilities in the offcentreline region, as well as the presence of different instability modes occurring along the centreline bulge, as was first identified by Choudhari et al (2009).…”

Section: Introductionmentioning

confidence: 99%

Transition mechanisms in cross-flow-dominated hypersonic flows with free-stream acoustic noise

Cerminara¹,

Sandham²

2020

J. Fluid Mech.

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“…The addition of acoustic noise caused unsteady waves to form on top of the vortices, causing their breakdown at the highest Reynolds numbers. More recent DNS simulations of Dinzl and Candler [38] have shown a difference between the centerline system of vortices, which is a baseflow property linked to the streamlines converging from the attachment line towards the centerline, and the crossflow vortices generated by surface roughness. When distributed roughness was added, a system of crossflow stationary vortices formed in the midspan region between the centerline and the attachment line, whose growth characteristics and wavelength were observed to be very sensitive to the roughness height and Reynolds number, respectively.…”

Section: Introductionmentioning

confidence: 99%

Receptivity to Freestream Acoustic Noise in Hypersonic Flow over a Generic Forebody

Cerminara

Durant

Thewis

et al. 2019

Journal of Spacecraft and Rockets

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Direct numerical simulations (DNS) of the Navier-Stokes equations have been performed to investigate the receptivity and breakdown mechanisms in a Mach 6 flow over a generic forebody geometry with freestream acoustic disturbances. The simulations are based on transition experiments carried out in April 2015 in the Boeing/AFOSR Mach 6 facility at Purdue University. A three-dimensional model for both fast and slow freestream acoustic waves with multiple frequencies and spanwise wavenumbers has been adopted in the numerical simulations, for which high-amplitude disturbances have been considered in order to simulate noisy wind tunnel conditions. The numerical results reveal similarities in comparison to the experimental observations, especially when slow acoustic waves are considered as freestream disturbances. In particular, slow acoustic waves have been found to induce the breakdown process via crossflow instabilities located in the off-centerline region, with formation of streamwise streaks. Fast acoustic waves, in contrast, appear more efficient in inducing earlier nonlinear growth through destabilisation of the boundary layer along the symmetry plane of the body.Receptivity is the internalization process of the external disturbances into the boundary layer in the form of instability modes, and determines the initial conditions for the downstream linear growth of the unstable modes. In the case of high-amplitude disturbances, nonlinearities can become predominant in the 3 of 31 American Institute of Aeronautics and Astronautics receptivity process, which would lead directly to nonlinear growth and rapid transition to turbulence. In some particular conditions, an intermediate route to transition (between a linear modal and a fully nonlinear process) is possible, i.e. transient growth, consisting of a non-modal growth of linear instabilities, as in the case of lift-up-induced streamwise streaks in conjunction with secondary instabilities and consequent nonlinear breakdown [1,2].The body leading edge is a highly-receptive zone, due to the non-parallel effects and the related shortscale streamwise variations of the mean flow, which, in turn, cause a wavelength-conversion process from the scale of the external forcing to that of the induced boundary-layer disturbances [3]. At hypersonic Mach numbers, however, the small difference in phase speed between the forcing waves and the boundary-layer dominant modes can lead to a direct excitation of these modes via a resonance mechanism at the leading edge [4,5,6,7], without the need of a wavelength-conversion mechanism. By applying Fedorov's notation [5], the internal mode generated at the leading edge through the receptivity to fast acoustic waves is called the fast mode, or mode F, while the mode associated to the slow acoustic waves is known as the slow mode, or mode S, which is the mode pertaining to the class of the unstable boundary-layer modes. In hypersonic boundary layers, different unstable modes can coexist, including the first mode, corresponding to the Tollmien-...

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Direct Simulation of Hypersonic Crossflow Instability on an Elliptic Cone

Cited by 54 publications

References 30 publications

Influence of Environmental Disturbances on Hypersonic Crossflow Instability on the HIFiRE-5 Elliptic Cone

Influence of Environmental Disturbances on Hypersonic Crossflow Instability on the HIFiRE-5 Elliptic Cone

Transition mechanisms in cross-flow-dominated hypersonic flows with free-stream acoustic noise

Receptivity to Freestream Acoustic Noise in Hypersonic Flow over a Generic Forebody

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