NASA Langley Experimental Aerothermodynamic Contributions to Slender and Winged Hypersonic Vehicles

Berry, Scott A.; Berger, Karen T.; Brauckmann, Gregory J.; Buck, Gregory M.; Hollis, Brian R.; Horvath, Thomas J.; Liechty, Derek S.; Mason, Michelle L.; Murphy, Kelly J.; Rhode, Matthew N.; Rufer, Shann J.; Wood, William A.

doi:10.2514/6.2015-0213

Cited by 2 publications

(2 citation statements)

References 49 publications

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“…For this purpose, a quasi-DNS (a fine wall-resolved implicit LES) is carried out at M = 6 . This value is much higher than those that are typically encountered in practical dense-gas applications [a remarkable exception being the high-Mach, high-Reynolds NASA Langley CF4 wind tunnel, dismantled in 2017, which used a light perfluorocarbon, CF4, as the working fluid up to M = 6 (Berry and Berger 2015)]; nevertheless, such severe operating conditions are of theoretical interest for highlighting dense gas effects. We also report wall-resolved LES results for a lower Mach number ( M = 2.25 ), more representative of values encountered in ORC applications, to investigate Mach number effects.…”

Section: Introductionmentioning

confidence: 93%

“…In this work we focus more particularly on so-called dense gas flows found in several engineering applications, ranging from energy production to high-Reynolds wind tunnels. A typical application is represented by energy conversion cycles like Organic Rankine Cycles (ORC) [see Colonna et al (2015) for a review] and heat pumps (Zamfirescu and Dincer 2009), but dense gases are also of interest for other applications, e.g., high-Reynolds wind tunnels (Bodenschatz et al 2014;Berry and Berger 2015;Corliss and Cole 1998). Dense gases are single-phase fluids with complex molecules, operating at pressure and temperature conditions of the same order of their thermodynamic critical point.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation of High-Speed Turbulent Boundary Layers of Dense Gases

Sciacovelli

Gloerfelt

Passiatore

et al. 2020

Flow Turbulence Combust

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High-speed turbulent boundary layers of a dense gas (PP11) and a perfect gas (air) over flat plates are investigated by means of direct numerical simulations and large eddy simulations. The thermodynamic conditions of the incoming flow are chosen to highlight dense gas effects, and laminar-to-turbulent transition is triggered by suction and blowing. In the paper, the behavior of the fully developed turbulent flow region is investigated. Due to the low characteristic Eckert number of dense gas flows ( Ec = U 2 ∞ ∕c p,∞ T ∞ ), the mean velocity profiles are largely insensitive to the Mach number and very close to the incompressible case even at high speeds. Second-order velocity statistics are also weakly affected by the flow Mach number and the velocity spectra are characterized by a secondary peak in the outer region of the boundary layer because of the higher local friction Reynolds number. Despite the incompressible-like velocity and Reynolds-stress profiles, the strongly nonideal thermodynamic and transport-property behavior of the dense gas results in unconventional distributions of the fluctuating thermo-physical quantities. Specifically, density and viscosity fluctuations reach a peak close to the wall, instead of vanishing as in perfect gas flows. Additionally, dense gas boundary layers exhibit higher values of the fluctuating Mach number and velocity divergence and a larger dilatational-to-solenoidal dissipation ratio in the near-wall region, which represents a major deviation from high-Mach-number perfect gas boundary layers. Other significant deviations are represented by the more symmetric probability distributions of fluctuating quantities such as the density and velocity divergence, due to the more balanced occurrence of strong expansion and compression events.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of High-Speed Turbulent Boundary Layers of Dense Gases

Sciacovelli

Gloerfelt

Passiatore

et al. 2020

Flow Turbulence Combust

View full text Add to dashboard Cite

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Design-oriented dynamic model of deployable fin under time-varying elevated temperature environment

Ren,

Wang,

Wang

et al. 2023

Aeronaut. j.

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Coupling of clearance joint and harsh aerodynamic heating environment is an inevitable nonlinear factor in folding mechanism of the fin of high-speed aircrafts that remarkably modifies natural frequencies and modes of vibration from the initial design state. However, accurately predicting dynamic properties of deployable fin with full consideration of these effects is not common industry practice. A practical semi-analytical model based on Hertz contact theory and ESDU-78035 model is proposed in this study to investigate high-temperature connection stiffness of local hinged–locked mechanisms. Material property degradation and clearance variation caused by thermal expansion are comprehensively considered and quantified in this model. Vibration characteristics of the assembled deployable fin are then solved using finite element method (FEM). The real-time evolutionary process of thermal mode of the fin is discussed. And natural frequencies of fixed-value and time-varying connection stiffness are compared. The simulation results of this study demonstrate that the relative error of structure temperature between the sequential approach and fully coupled simulations is less than 6.98%. The connection stiffness (slope of the load-displacement curve) of the folding mechanism under high temperature conditions decreases by 3.52%, and the variation is mainly caused by the degradation of the elastic modulus of the material, while the clearance change due to the thermal expansion has no significant effect on the slope. The natural frequency of the deployable fin exhibits an inverse correlation with the temperature change trend, and the first three frequencies decrease by 1.67, 7.75, and 16.28 Hz compared to the initial value, respectively.

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NASA Langley Experimental Aerothermodynamic Contributions to Slender and Winged Hypersonic Vehicles

Cited by 2 publications

References 49 publications

Numerical Investigation of High-Speed Turbulent Boundary Layers of Dense Gases

Numerical Investigation of High-Speed Turbulent Boundary Layers of Dense Gases

Design-oriented dynamic model of deployable fin under time-varying elevated temperature environment

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