Boundary-layer transition prediction toolkit

Malik, Mujeeb R.

doi:10.2514/6.1997-1904

Cited by 34 publications

(9 citation statements)

References 59 publications

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“…In this paper, we explore the above possibility within the limited scope of a small set of experiments performed in the low-speed ASU wind tunnel. For the conditions of the ASU experiment, we first compute (following the approach adopted by Malik &Li 1992, and) the nonlinear evolution of stationary crossflow disturbances and find good agreement with the experimental data. The boundary-layer flow distorted by the presence of crossflow vortices is analysed for secondary instability modes.…”

Section: Introductionmentioning

confidence: 90%

“…'chordwise absolute instability'. The works of Lingwood (1997) and Lin, Li & Malik (1999) (see also Malik 1997) show that, in swept-wing boundary layers, pinch points occur in the chordwise direction near the leading edge but only at relatively large leading-edge Reynolds numbers (R > 540). Therefore, the underlying boundary-layer flow in the ASU experiment must be convectively unstable although, of course, the possibility that the mean flow distorted by the primary modes might be absolutely unstable cannot be ruled out without further investigation.…”

Section: Introductionmentioning

confidence: 98%

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Secondary instability of crossflow vortices and swept-wing boundary-layer transition

et al. 1999

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Crossflow instability of a three-dimensional boundary layer is a common cause of transition in swept-wing flows. The boundary-layer flow modified by the presence of finite-amplitude crossflow modes is susceptible to high-frequency secondary instabilities, which are believed to harbinger the onset of transition. The role of secondary instability in transition prediction is theoretically examined for the recent swept-wing experimental data by Reibert et al. (1996). Exploiting the experimental observation that the underlying three-dimensional boundary layer is convectively unstable, non-linear parabolized stability equations are used to compute a new basic state for the secondary instability analysis based on a two-dimensional eigenvalue approach. The predicted evolution of stationary crossflow vortices is in close agreement with the experimental data. The suppression of naturally dominant crossflow modes by artificial roughness distribution at a subcritical spacing is also confirmed. The analysis reveals a number of secondary instability modes belonging to two basic families which, in some sense, are akin to the ‘horseshoe’ and ‘sinuous’ modes of the Görtler vortex problem. The frequency range of the secondary instability is consistent with that measured in earlier experiments by Kohama et al. (1991), as is the overall growth of the secondary instability mode prior to the onset of transition (e.g. Kohama et al. 1996). Results indicate that the N-factor correlation based on secondary instability growth rates may yield a more robust criterion for transition onset prediction in comparison with an absolute amplitude criterion that is based on primary instability alone.

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 98%

Secondary instability of crossflow vortices and swept-wing boundary-layer transition

et al. 1999

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“…This motivates extensive experimental, theoretical and numerical studies of the transition at supersonic and hypersonic speeds. The progress made in the transition prediction methodology for high speeds is reviewed by Malik, Zang & Bushnell (1990), Malik (1997) and Fedorov (2011). The success of transition prediction depends on a fundamental understanding of the relevant physical mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Receptivity of a high-speed boundary layer to temperature spottiness

et al. 2013

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Two-dimensional direct numerical simulation (DNS) of the receptivity of a flat-plate boundary layer to temperature spottiness in the Mach 6 free stream is carried out. The influence of spottiness parameters on the receptivity process is studied. It is shown that the temperature spots propagating near the upper boundary-layer edge generate mode F inside the boundary layer. Further downstream mode F is synchronized with unstable mode S (Mack second mode) and excites the latter via the inter-modal exchange mechanism. Theoretical assessments of the mode F amplitude are made using the biorthogonal eigenfunction decomposition method. The DNS results agree with the theoretical predictions. If the temperature spots are initiated in the free stream and pass through the bow shock, the dominant receptivity mechanism is different. The spot–shock interaction leads to excitation of acoustic waves, which penetrate into the boundary layer and excite mode S. Numerical simulations show that this mechanism provides the instability amplitudes an order of magnitude higher than in the case of receptivity to the temperature spots themselves.

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“…A review of the experimental and theoretical studies of turbulence formation in supersonic wall flows and methods for calculating the transition Reynolds numbers can be found in [2,3]. At low external disturbance levels, the transition process is due to the excitation and development of unstable disturbances.…”

mentioning

confidence: 99%

Numerical modeling of the disturbances of the separated flow in a rounded compression corner

Егоров¹,

Новиков²,

Федоров³

2006

Fluid Dyn

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Numerical modeling of the time-dependent supersonic flow over a compression corner with different roundness radii is performed on the basis of the solution of the two-dimensional Navier-Stokes equations in the regimes corresponding to local boundary layer separation. The development of unstable disturbances generated by local periodic injection/suction in the preseparated boundary layer is calculated. The results are compared with those of similar calculations for a flat plate. It is shown that the natural oscillations of the boundary-layer second mode stabilize in the separation zone and grow intensely downstream of the reattachment point. The acoustic modes excited within a separation bubble are studied using numerical calculations and an asymptotic analysis.

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Boundary-layer transition prediction toolkit

Cited by 34 publications

References 59 publications

Secondary instability of crossflow vortices and swept-wing boundary-layer transition

Secondary instability of crossflow vortices and swept-wing boundary-layer transition

Receptivity of a high-speed boundary layer to temperature spottiness

Numerical modeling of the disturbances of the separated flow in a rounded compression corner

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