Transonic characteristics of a humped airfoil

Tai, Tsze C.; Huson, Gregory G.; Hicks, R. M.; Gregorek, G. M.

doi:10.2514/6.1987-1239

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…The potential of these humped supercritical aerofoils to improve off-design performance (i.e. delay buffet and increase drag-divergence Mach number) was confirmed by experiments in the 1980s [35], although the results also showed that there was significant room for further improvement. In 1992, Ashill et al [2] were the first to consider SCBs as a method for wave drag reduction on laminarflow aerofoils.…”

Section: Historical Backgroundmentioning

confidence: 68%

“…As previously mentioned, the concept of a SCB originated from studies investigating ways to increase the drag-divergence Mach number of transonic aerofoils [34,35]. Since then, many studies have considered the 'robustness' of 2-D and 3-D SCBs by testing them at both design conditions as well as a range of off-design conditions representing both near-cruise conditions [6,26] as well as more extreme cases near the buffet boundary [10].…”

Section: Performancementioning

confidence: 99%

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Review of research into shock control bumps

Bruce

Colliss

2014

Shock Waves

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This paper presents a review of research on shock control bumps (SCBs), a class of flow control device with potential for application to transonic wings. Beginning with a brief review of the origins of the SCB concept, the primary focus is on the more recent studies from the last decade. Results from both experimental and numerical work are considered and the synergy between these two approaches to SCB research is critically explored. It is shown that the aerodynamic performance enhancement potential of SCBs, namely their capacity for drag reduction and delaying the onset of buffet for transonic wings, has been widely demonstrated in the literature, as has the high sensitivity of SCB performance to flow conditions including shock strength and position, and post-shock adverse pressure gradient. These characteristic features of SCBs are relatively well explained in terms of the flow physics that have been observed for different bump geometries. This stems from a number of studies that have focused on the balance of viscous and inviscid flow features and also the mechanism by which finite span SCBs generate streamwise vorticity. It is concluded that our understanding of SCBs is reaching an advanced level of maturity for SCBs in simple configurations and steady flow fields. However, SCB performance in unsteady flow and on swept wings requires further investigation before the concept can be considered a viable candidate for transonic wings. These investigations should adopt a multi-disciplinary approach combining carefully designed experiments and targeted computations. Finally, two concepts for future SCB research are suggested: the adaptive SCB and SCBs in engine intakes.Communicated by A. Hadjadj.

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Section: Historical Backgroundmentioning

confidence: 68%

Section: Performancementioning

confidence: 99%

Review of research into shock control bumps

Bruce

Colliss

2014

Shock Waves

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“…The earliest example of shock control bump usage is in the design of the dromedaryfoil in the 1970s (14,15) . This was a modified supercritical aerofoil with a bump added in an attempt to increase its drag divergence Mach number.…”

Section: Shock Control Bumpsmentioning

confidence: 99%

Using shock control bumps to improve engine intake performance and operability

et al. 2020

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Shock control bumps can be used to control and weaken the shock waves that form on engine intakes at high angles of attack. In this paper, it is demonstrated how shock control bumps applied to an engine intake can reduce or eliminate shock-induced separation at high incidence, and also increase the incidence at which critical separation occurs. Three-dimensional Reynolds-average Navier–Stokes (RANS) simulations are used to model the flow through a large civil aircraft engine intake at high incidence. The variation in shock strength and separation with incidence is first studied, along with the flow distribution around the nacelle. An optimisation process is then employed to design shock control bumps that reduce shock strength and separation at a fixed high incidence condition. The bump geometry is allowed to vary in shape, size, streamwise position and circumferential direction around the nacelle. This is shown to be key to the success of the shock control geometry. A further step is then taken, using the optimisation methodology to design bumps that can increase the incidence at which critical separation occurs. It is shown that, by using this approach, the operating range of the engine intake can be increased by at least three degrees.

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On the Application of Contour Bumps for Transonic Drag Reduction (Invited)

Milholen

Owens

2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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The effect of discrete contour bumps on reducing the transonic drag at off-design conditions on an airfoil have been examined. The research focused on fully-turbulent flow conditions, at a realistic flight chord Reynolds number of 30 million. State-of-the-art computational fluid dynamics methods were used to design a new baseline airfoil, and a family of fixed contour bumps. The new configurations were experimentally evaluated in the 0.3-m Transonic Cryogenic Tunnel at the NASA Langley Research center, which utilizes an adaptive wall test section to minimize wall interference. The computational study showed that transonic drag reduction, on the order of 12% -15%, was possible using a surface contour bump to spread a normal shock wave. The computational study also indicated that the divergence drag Mach number was increased for the contour bump applications. Preliminary analysis of the experimental data showed a similar contour bump effect, but this data needed to be further analyzed for residual wall interference corrections.

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Transonic characteristics of a humped airfoil

Cited by 3 publications

References 2 publications

Review of research into shock control bumps

Review of research into shock control bumps

Using shock control bumps to improve engine intake performance and operability

On the Application of Contour Bumps for Transonic Drag Reduction (Invited)

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