Hypersonic Real-Gas Effects on Transition

Hornung, H. G.

doi:10.1007/978-1-4020-4150-1_32

Cited by 7 publications

(5 citation statements)

References 12 publications

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“…Studies of laminar-turbulent transition with a focus on high-temperature gas effects have mostly been based on experiments 11,14 or linear theories. 15,17,24,35 Theoretical approaches rely on numerical simulations in that they require a preceding computation of a steady-state flow, for which a number of numerical methods exist.…”

Section: Introductionmentioning

confidence: 99%

A high-order numerical method to study hypersonic boundary-layer instability including high-temperature gas effects

et al. 2011

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Prediction of laminar-turbulent transition is a key factor in the design of the heat shield of vehicles (re-)entering a planetary atmosphere. To investigate the transition by means of numerical simulation, accurate and efficient computational methods are necessary. Here, the compressible Navier-Stokes equations are solved for a gas where properties such as specific heat, thermal conductivity, viscosity, and specific gas constant depend on one or two thermodynamic variables. Our approach models a mixture of perfect gases in local thermodynamic equilibrium. The gas properties are provided either by means of direct calls to a library based on statistical mechanics and kinetic theory or indirectly in the form of look-up tables. In the first part of the paper, our method of handling a high-temperature gas in thermochemical equilibrium is described and verified. In the second part, the method is applied to the investigation of linear and non-linear boundary-layer instability. We carry out numerical simulations for a laminar flat-plate boundary layer at Mach 10 with a small, convectively amplified perturbation for both Earth and Martian atmospheres. Amplification of the perturbations shows favorable agreement with results obtained from linear theory. The secondary instability of the boundary layer in the presence of a large-amplitude two-dimensional wave is investigated. We observe that the non-linear mechanism of fundamental resonance becomes active and leads to a strong increase in amplification of three-dimensional disturbance waves. © 2011 American Institute of Physics

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Section: Introductionmentioning

confidence: 99%

A high-order numerical method to study hypersonic boundary-layer instability including high-temperature gas effects

et al. 2011

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“…The influence of high-temperature gas effects on transition has not been unravelled, and evidence for a transition delay as well as enhancement exists (Stuckert & Reed 1994;Germain & Hornung 1997;Malik 2003;Hornung 2006). This contradiction 36 O. Marxen, G. Iaccarino and T. E. Magin may be attributed to the large number of governing parameters as well as physical effects involved.…”

Section: Introductionmentioning

confidence: 81%

Direct numerical simulations of hypersonic boundary-layer transition with finite-rate chemistry

2014

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The paper describes a numerical investigation of linear and nonlinear instability in high-speed boundary layers. Both a frozen gas and a finite-rate chemically reacting gas are considered. The weakly nonlinear instability in the presence of a large-amplitude two-dimensional wave is investigated for the case of fundamental resonance. Depending on the amplitude of this two-dimensional primary wave, strong growth of oblique secondary perturbations occurs for favourable relative phase differences between the two. For essentially the same primary amplitude, secondary amplification is almost identical for a reacting and a frozen gas. Therefore, chemical reactions do not directly affect the growth of secondary perturbations, but only indirectly through the change of linear instability and hence amplitude of the primary wave. When the secondary disturbances reach a sufficiently large amplitude, strongly nonlinear effects stabilize both primary and secondary perturbations. © Cambridge University Press 2014

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“…This would be a new variable, requiring an additional equation for its computation. However, as is shown in Figure 10 The SST turbulence model [12] is tested in this paper for all the three cases in Table 1. Each case is computed by two gas models, namely the perfect gas model with a constant γ =1.4, and the variable γ gas model, in which γ is calculated by eq.…”

Section: The Application Of Turbulence Modeling For Turbulent Flow Ofmentioning

confidence: 99%

“…Jia and Cao [11] also studied the influence of variable specific heat on the stability of hypersonic boundary layers. Hornung [12] studied the problem of hypersonic real gas effect on transition. Apparently, the variation of specific heat also influences the turbulence characteristics in turbulent boundary layers.…”

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confidence: 99%

The effect of high temperature induced variation of specific heat on the hypersonic turbulent boundary layer and its computation

Dong

Zhou

2010

Sci. China Phys. Mech. Astron.

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For hypersonic vehicles, as the temperature in its boundary layer usually exceeds 600 K, for which the molecular vibrational degree of freedom is excited, the perfect gas model is no longer valid. In this paper, the effect of high temperature induced variation of specific heat on the hypersonic turbulent boundary layer of flat plates is investigated by direct numerical simulations with the perfect gas model, i.e. with constant specific heat, as well as with a variable specific heat gas model. The comparison of the results from the two gas models has found that the effect of the variation of specific heat on the velocity of the turbulent boundary layers is relatively small, while its effect on temperature, such as the mean temperature, the temperature fluctuations, is appreciable. It is also found that the mean specific heat is quite close to the specific heat calculated by using the mean temperature, indicating that it is possible to do turbulence modeling. The modeling is done under the variable specific heat gas model with the mean temperature as the variable. The feasibility of such consideration is verified by applying the SST model for variable specific heat turbulence computation.hypersonic, turbulent boundary layer, specific heat, direct numerical simulation, SST model

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Hypersonic Real-Gas Effects on Transition

Cited by 7 publications

References 12 publications

A high-order numerical method to study hypersonic boundary-layer instability including high-temperature gas effects

A high-order numerical method to study hypersonic boundary-layer instability including high-temperature gas effects

Direct numerical simulations of hypersonic boundary-layer transition with finite-rate chemistry

The effect of high temperature induced variation of specific heat on the hypersonic turbulent boundary layer and its computation

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