Type III and type IV shock/shock interferences: theoretical and experimental aspects

Grasso, Francesco; Purpura, C.; Chanetz, Bruno; Délery, Jean

doi:10.1016/s1270-9638(02)00005-6

Cited by 54 publications

(30 citation statements)

References 24 publications

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“…Transitional supersonic free-shear flows of technological interest include jets, wakes and mixing layers. They occur in the supersonic exhaust flow from gas-turbine engines (Tam 1995), streak breakdown in tripped supersonic boundary † Email address for correspondence: massa@uta.edu layers (Berry et al 2001), turbulization and reattachment in hypersonic separated flows (Holden 1966;Horvath, Berry & Merski 2004), and jets supported by type IV (Edney) shock-shock interactions (Grasso et al 2003).…”

Section: Introductionmentioning

confidence: 99%

On the effects of finite-rate carbon/oxygen chemistry on supersonic jet instability

Massa

Ravindran

2012

J. Fluid Mech.

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The instability of high-temperature jets is studied because of its importance to the analysis of gas-turbine engine exhaust flow, shock-shock interaction and bypass transition. The focus is on fluid-chemistry coupling, where the chemical time scales are supported by both reactive and inelastic molecular processes. The former are associated with dissociation/exchange reactions, while the latter are associated with transfers of vibrational quanta. The interaction affects both the instability growth rate and acoustic feedback by sustaining thermo-acoustic damping. Resonance conditions are identified as those that yield the maximum damping against the Damköhler number. The main results of the present study are the explanation of the dichotomy between vortical and acoustic modes in relation to the thermo-acoustic damping, and the analysis of the resonance condition as it depends on the physico-chemical properties of carbon/oxygen mixtures. The ability of a mode to support thermo-acoustic damping is related to the local convective Mach number of its most amplified frequency, and thus to the phenomenon of acoustic trapping in the jet core. Regarding the second issue, carbon dioxide acts as the best damper at low jet temperatures T j ≈ 1000 K, where the vibrational relaxation is the main chemical scale, and up to T j = 3500 K because its reactive chemistry resonates with the fluid fluctuation at a lower temperature than the dissociation of O 2 . At higher temperatures, oxygen is the best damper because of the larger endothermicity of the reactions it supports.

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Section: Introductionmentioning

confidence: 99%

On the effects of finite-rate carbon/oxygen chemistry on supersonic jet instability

Massa

Ravindran

2012

J. Fluid Mech.

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“…The selected flow configuration is a type IV shock-shock interaction [45], as classified by Edney [46]. This type of interaction arises when a weak (with the term "weak" we here mean an oblique shock featuring a shock angle σ which is smaller than that corresponding to the maximum flow deflection for the given free-stream Mach number) oblique shock meets the bow shock produced by a supersonic stream impinging on a blunt nosed body.…”

Section: Unstructured Grid: Anisotropic Mesh Adaptationmentioning

confidence: 99%

The Role of Mesh Generation, Adaptation, and Refinement on the Computation of Flows Featuring Strong Shocks

Bonfiglioli

Paciorri

Mascio

2012

Modelling and Simulation in Engineering

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Within a continuum framework, flows featuring shock waves can be modelled by means of either shock capturing or shock fitting. Shock-capturing codes are algorithmically simple, but are plagued by a number of numerical troubles, particularly evident when shocks are strong and the grids unstructured. On the other hand, shock-fitting algorithms on structured grids allow to accurately compute solutions on coarse meshes, but tend to be algorithmically complex. We show how recent advances in computational mesh generation allow to relieve some of the difficulties encountered by shock capturing and contribute towards making shock fitting on unstructured meshes a versatile technique.

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“…The Edney type IV interaction is the most critical shock-shock interaction in terms of the aerothermal loads on the wall [3]. Figure 1a shows a schematic drawing of the interaction, including the key flow features.…”

Section: Introductionmentioning

confidence: 99%

“…When the impinging shock wave is moved upward, the jet begins to bend upward along the cylinder surface. This state is frequently characterized as a type IVa interaction [3].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Unsteady Edney Type IV and VII Shock–Shock Interactions

2016

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Edney type IV and type VII shock-shock interactions are complex hypersonic flow phenomena. They are characterized by a supersonic jet that reaches far into the flowfield. An experimental investigation of the inner jet structure is difficult, especially in cases where the jet is subject to high-frequency unsteady movements. The present paper provides insight into the jet structure and its movement by means of a highly resolved computational fluid dynamics analysis in thermochemical nonequilibrium that significantly exceeds the resolution of existing publications. Simulations of an Edney type IV interaction in nitrogen flow are presented. Advanced adaptation strategies allow for the identification and analysis of the mechanisms of the jet unsteadiness, resulting in a new classification of the unsteady flowfield behavior with respect to the periodic jet movement. This classification is based not only on wall quantities, but also on the core flowfield. The computations are supplemented by a grid sensitivity study. The second configuration is an Edney type VII interaction. This shock-shock interaction type was observed and defined in nitrogen flow by Yamamoto et al (Numerical Investigation of Shock/Vortex Interaction in Hypersonic Thermochemical Nonequilibrium Flow, Journal of Spacecraft and Rockets, Vol. 36, No. 2, 1999, pp. 240-246. The present results demonstrate that this interaction may also be observed in carbon-dioxide-dominated flow with a gas composition similar to the Martian atmosphere. The results provide insight into the jet structure of this less known interaction.

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Type III and type IV shock/shock interferences: theoretical and experimental aspects

Cited by 54 publications

References 24 publications

On the effects of finite-rate carbon/oxygen chemistry on supersonic jet instability

On the effects of finite-rate carbon/oxygen chemistry on supersonic jet instability

The Role of Mesh Generation, Adaptation, and Refinement on the Computation of Flows Featuring Strong Shocks

Investigation of Unsteady Edney Type IV and VII Shock–Shock Interactions

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