Boundary-Layer Displacement and Leading-Edge Bluntness Effects in High-Temperature Hypersonic Flow

Cheng, H. K.; Hall, J. G.; Golian, T. C.; Hertzberg, A.

doi:10.2514/8.9002

Cited by 169 publications

(48 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Earlier studies in the 1950s, 1960s and 1970s mainly dealt with bluntness effects on flow transition (Moeckel 1957; Nagamatsu, Graber & Sheer 1966; Softley 1969; Pate 1977; Stetson 1978), SWBLI (Bertram 1954; Bertram & Henderson Jr 1958; Cheng et al. 1961; Holloway, Sterrett & Creekmore 1965; Holden 1966; Townsend 1966; Edney 1968; Edwards & Anders 1968; Holden 1971; Gray & Rhudy 1972) or the combined effect of bluntness and incidence angle (Bertram & Henderson Jr 1958; Creager 1959; Cheng et al. 1961; Nagamatsu et al.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of bluntness effects on laminar leading edge separation in hypersonic flow

Khraibut¹,

Gai²,

Neely³

2019

J. Fluid Mech.

View full text Add to dashboard Cite

Bluntness effects on laminar hypersonic leading edge separation are investigated numerically at Mach number $M\approx 10$, unit Reynolds number $Re=1.3\times 10^{6}~\text{m}^{-1}$, specific enthalpy $h_{o}=3.1~\text{MJ}~\text{kg}^{-1}$ and wall-to-stagnation temperature ratio $T_{w}/T_{o}=0.1$. Such effects are important from an experimental point of view and because bluntness can affect a separated flow favourably or adversely. In this study, two blunt leading edge cases of small radius ($15~\unicode[STIX]{x03BC}\text{m}$) and large radius ($100~\unicode[STIX]{x03BC}\text{m}$) are investigated. A comparison with the idealised sharp leading edge case is also given. General flow features and surface parameters such as the shear stress, pressure and heat flux are presented and analysed. The results have also been interpreted in terms of Cheng’s displacement-bluntness similitude parameter affecting the size of separation. Previous experiments by Holden delineated small and large bluntness effects based on Cheng’s parameter and considering small to moderate separated regions. In this study, leading edge separation was found to suppress the favourable effect of bluntness in delaying separation. Bluntness, furthermore, seemed to promote the appearance of secondary vortices within a main separated region. Analysis of reverse flow boundary layer profiles such as velocity, pressure and temperature is also given. It is shown that bluntness accentuates large transverse gradients. This in turn adversely effects the reverse flow boundary layer leading to the appearance of secondary vortices.

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical study of bluntness effects on laminar leading edge separation in hypersonic flow

Khraibut¹,

Gai²,

Neely³

2019

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…III B 2). 11 Combining the local flat plate similarity theory of Lees 11 with the Newton-Busemann pressure approximation, Cheng 12 developed a theoretical model to predict boundary layer quantities on blunted flat plates at an angle of attack in hypersonic flow. This method was extended to curved surfaces by Stollery.…”

Section: Introductionmentioning

confidence: 99%

Scaling of heat transfer augmentation due to mechanical distortions in hypervelocity boundary layers

Flaherty

Austin

2013

Physics of Fluids

View full text Add to dashboard Cite

We examine the response of hypervelocity boundary layers to global mechanical distortions due to concave surface curvature. Surface heat transfer and visual boundary layer thickness data are obtained for a suite of models with different concave surface geometries. Results are compared to predictions using existing approximate methods. Near the leading edge, good agreement is observed, but at larger pressure gradients, predictions diverge significantly from the experimental data. Up to a factor of five underprediction is reported in regions with greatest distortion. Curve fits to the experimental data are compared with surface equations. We demonstrate that reasonable estimates of the laminar heat flux augmentation may be obtained as a function of the local turning angle for all model geometries, even at the conditions of greatest distortion. This scaling may be explained by the application of Lees similarity. As a means of introducing additional local distortions, vortex generators are used to impose streamwise structures into the boundary layer. The response of the large scale vortices to an adverse pressure gradient is investigated. Surface streak evolution is visualized over the different surface geometries using fast response pressure sensitive paint. For a flat plate baseline case, heat transfer augmentation at similar levels to turbulent flow is measured. For the concave geometries, increases in heat transfer by factors up to 2.6 are measured over the laminar values. The scaling of heat transfer with turning angle that is identified for the laminar boundary layer response is found to be robust even in the presence of the imposed vortex structures.

show abstract

“…The method of Boger & Aiello [17] was used to predict the surface pressure level. This method is based on the theory of Cheng et al (CT) [18], combining the 3D effect of nose bluntness (blast wave theory) and the boundary layer displacement (strong interaction theory).…”

Section: A Pressure Distribution On the Forward Wedge Surface (S1)mentioning

confidence: 99%

Drag Estimation on Wedge-Shaped Protuberances in High-Speed Flows

Kshitij

Prince

Stollery

2020

AIAA Scitech 2020 Forum

View full text Add to dashboard Cite

A semi-empirical method is developed to estimate drag on wedge-shaped projections in hypersonic flow. Force balance measurements from gun tunnel tests directly measure total drag on blunt wedges, where the boundary layer and the entropy layer are weakly coupled. Detailed flowfield analysis from numerical simulations provides estimated locations of peak pressure ratio and skin friction. Schlieren images are used for detecting incipient separation in incoming flows with laminar and turbulent boundary layers. Test results indicate presence of local hotspots at reattachment points of strong detached shocks on wedge compression ramp, and of primary and secondary vortical structures around lateral faces. Total drag is found to decrease with decreasing bluntness but increasing slenderness in wedges tend to increase skin friction drag.

show abstract

Boundary-Layer Displacement and Leading-Edge Bluntness Effects in High-Temperature Hypersonic Flow

Cited by 169 publications

References 30 publications

Numerical study of bluntness effects on laminar leading edge separation in hypersonic flow

Numerical study of bluntness effects on laminar leading edge separation in hypersonic flow

Scaling of heat transfer augmentation due to mechanical distortions in hypervelocity boundary layers

Drag Estimation on Wedge-Shaped Protuberances in High-Speed Flows

Contact Info

Product

Resources

About