Toward Designing with Three-Dimensional Bumps for Lift/Drag Improvement and Buffet Alleviation

Eastwood, Jeremy P.; Jarrett, Jerome P.

doi:10.2514/1.j051740

Cited by 52 publications

(66 citation statements)

References 19 publications

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“…5b) yields a 'cleaner' two-step pressure rise which is less detrimental to the boundary layer [26]. Figure 6 presents results from two numerical studies [10,13], both of which illustrate this beneficial impact of a 2-D SCB on the streamwise pressure distribution over the upper surface of a supercritical aerofoil.…”

Section: -D Scbmentioning

confidence: 99%

“…Such observations and comments are invariably unquantified; with most studies considering, at best, a small number of 'representative' test cases with different flow conditions. However, one recent study by Eastwood and Jarrett [10] has attempted to address this with a more quantified approach. An element of their study (which is discussed in more detail in Sect.…”

Section: Performancementioning

confidence: 99%

“…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]. Results from these studies consist of a mixture of qualitative comments and reported measurements (usually L/D) that quantify the sensitivity of SCB efficiency to flow conditions, such as the results previously shown in Fig.…”

Section: Performancementioning

confidence: 99%

“…However, non-optimal shock locations yield significantly increased levels of viscous drag and can Fig. 6 Results from: a Milholen and Owens [13]; b Eastwood and Jarrett [10], reproduced with permission from Jeremy Eastwood also promote boundary layer separation [26]. Despite this, some studies have argued that 2-D SCBs can still have a positive impact on off-design performance in one of the two ways: (1) Delaying the onset of transonic buffet by breaking up large regions of separated flow and inhibiting communication between an oscillating shock and an aerofoil's trailing edge [2,4,18]; and, (2) In the case of a straight ramp-type design, improving shock stability by effectively anchoring the front shock leg [17].…”

Section: -D Scbmentioning

confidence: 99%

“…Recently, many studies have focused on comparing the performance of arrays of 3-D SCBs with single 2-D devices [10,17,26,27,29,38]. In general, these studies have shown that, while 2-D SCBs offer the maximum potential benefit in terms of design-point drag reduction for a transonic wing, an array of 3-D SCBs is able to deliver very similar levels of performance benefit (in terms of wave drag saving) with the added advantages of reduced installation cost and complexity and improved robustness to variations in shock position [26,29].…”

Section: -D Versus 3-dmentioning

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: -D Scbmentioning

confidence: 99%

Section: Performancementioning

confidence: 99%