Transonic buffet instability: From two-dimensional airfoils to three-dimensional swept wings

Paladini, Edorado; Beneddine, Samir; Dandois, Julien; Sipp, Denis; Robinet, Jean-Christophe

doi:10.1103/physrevfluids.4.103906

Cited by 51 publications

(70 citation statements)

References 39 publications

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“…But since the mean flow is axisymmetric and the mesh is homogeneous in the azimuthal direction, the Jacobian operator may be rearranged in a block-diagonal form as proposed by Schmid, de Pando & Peake (2017) to make the computation significantly cheaper. This cost-reduction method, which has also been used in Paladini et al (2019), is briefly presented below.…”

Section: Azimuthal Decomposition Of the Resolvent Analysismentioning

confidence: 99%

Transition scenario in hypersonic axisymmetrical compression ramp flow

et al. 2020

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Section: Azimuthal Decomposition Of the Resolvent Analysismentioning

confidence: 99%

Transition scenario in hypersonic axisymmetrical compression ramp flow

et al. 2020

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“…Outboard-travelling shock waves can also be connected to so-called "buffet cells" [21][22][23]. Not everything is different, however, since recent studies for swept wings also exhibit a sharp spectral peak comparable to unswept cases [24], where the mode associated with the broadband swept-wing behaviour seems to be driven by flow-separation phenomena and converges towards a zero-frequency mode for decreasing sweep angles [25]. These results suggest that there is more to learn from unswept cases, as they not only capture phenomena that are still not fully understood, but are connected to more general swept-wing configurations.…”

Section: Introductionmentioning

confidence: 99%

Wide domain simulations of flow over an unswept laminar wing section undergoing transonic buffet

Zauner

Sandham

2020

Phys. Rev. Fluids

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Transonic buffet is an unsteady flow phenomenon that limits the safe flight envelope of modern aircraft. Scale-resolving simulations with span-periodic boundary conditions can provide detailed insight into the flow physics associated with buffet and can help to calibrate simplified models that are needed, for example, to develop more efficient wings based on laminar-flow supercritical sections. However, such simulations are often feasible only for severely restricted spanwise domains. In the current contribution, we analyse an unswept laminar-flow wing section (of Dassault Aviation's V2C profile) at a moderate Reynolds number of Re = 500,000 and a Mach number of M = 0.7 with spanwise domains equal to 5% and 100% of the airfoil chord. An implicit large-eddy simulation methodology, using a spectral error estimator to control the action of a high-order filter, is first validated against direct numerical simulations and then used for the domain width study. Quantitative differences, due to domain size, include an increase in amplitude and regularity of the buffet oscillations in the wider domain. Nevertheless, space-time analysis shows that key physical phenomena such as upstream-propagating shock waves are properly represented in the narrow domain and there is limited sensitivity to domain size of the aerodynamic coefficients. Even in the very wide domain, which is an order of magnitude wider than the largest turbulent structures measured at the trailing edge, certain features remain two-dimensional, including the shock and expansion waves that interact with the boundary layer upstream of transition. The transition mechanism is found to have subtle variations during a typical buffet cycle, with Kelvin-Helmholtz structures prominent during low-lift phases and oblique modes developing behind shock/boundarylayer interactions during high-lift phases. The availability of the wide-domain data is used for further study of the buffet mechanism, considering phase-averaged data and instantaneous flow fields to show the global structure of the buffet oscillation.

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“…Three-dimensional global stability analyses were attempted by Iorio et al (2014), but an unstable mode specific to 3-D buffet was not found. Recently, global stability analysis was applied to infinite swept wings using a spanwise periodicity assumption (Crouch, Garbaruk & Strelets 2018, 2019Paladini et al 2019a;Plante et al 2019a) and fully 3-D analyses (Paladini 2018;He & Timme 2020). Stability analysis has also been applied to the NASA Common Research Model by Timme (2018Timme ( , 2019.…”

Section: Introductionmentioning

confidence: 99%