Direct numerical simulation of controlled transition in a flat-plate boundary layer

Rist, Ulrich; Fasel, Hermann F.

doi:10.1017/s0022112095003284

Cited by 195 publications

(126 citation statements)

References 16 publications

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“…Since then, many experimental (Kline et al 1967;Head & Bandyopadhyay 1981;Borodulin, Kachanov & Roschektayev 2011) and numerical (Rist & Fasel 1995;Wu & Moin 2009;Sayadi, Hamman & Moin 2013) studies of transitional and turbulent boundary layers have reaffirmed that indeed coherent structures are present in these flows and play an important role in the mass, momentum and energy transport (for a review we refer to Hussain (1986) and Robinson (1991)). There has been a great deal of effort to extract coherent structures from experimental and numerical data; however, many of the identification methods rely on a priori knowledge of the specific form of the structure.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to the K-type transition, where these vortices are aligned, the H-type transition is characterized by staggered arrangements of Λ-vortices (Saric 1986). The structures that appear in the early stages of these transitional regimes are well documented, both experimentally and numerically (Borodulin & Kachanov 1995;Rist & Fasel 1995), which makes them suitable for validation purposes. Moreover, DMD can be considered as an optimal phase-averaging process and can be used in the context of a triple decomposition (Reynolds & Hussain 1972), further described in § 4.1, to directly account for the contribution of the coherent structures to the nonlinear term in the Navier-Stokes equations.…”

Section: Introductionmentioning

confidence: 99%

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Reduced-order representation of near-wall structures in the late transitional boundary layer

et al. 2014

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Direct numerical simulations (DNS) of controlled H-and K-type transitions to turbulence in an M = 0.2 (where M is the Mach number) nominally zero-pressuregradient and spatially developing flat-plate boundary layer are considered. Sayadi, Hamman & Moin (J. Fluid Mech., vol. 724, 2013, pp. 480-509) showed that with the start of the transition process, the skin-friction profiles of these controlled transitions diverge abruptly from the laminar value and overshoot the turbulent estimation. The objective of this work is to identify the structures of dynamical importance throughout the transitional region. Dynamic mode decomposition (DMD) (Schmid, J. Fluid Mech., vol. 656, 2010, pp. 5-28) as an optimal phase-averaging process, together with triple decomposition (Reynolds & Hussain, J. Fluid Mech., vol. 54 (02), 1972, pp. 263-288), is employed to assess the contribution of each coherent structure to the total Reynolds shear stress. This analysis shows that low-frequency modes, corresponding to the legs of hairpin vortices, contribute most to the total Reynolds shear stress. The use of composite DMD of the vortical structures together with the skin-friction coefficient allows the assessment of the coupling between near-wall structures captured by the low-frequency modes and their contribution to the total skin-friction coefficient. We are able to show that the low-frequency modes provide an accurate estimate of the skin-friction coefficient through the transition process. This is of interest since large-eddy simulation (LES) of the same configuration fails to provide a good prediction of the rise to this overshoot. The reduced-order representation of the flow is used to compare the LES and the DNS results within this region. Application of this methodology to the LES of the H-type transition illustrates the effect of the grid resolution and the subgrid-scale model on the estimated shear stress of these low-frequency modes. The analysis shows that although the shapes and frequencies of the low-frequency modes are independent of the resolution, the amplitudes are underpredicted in the LES, resulting in underprediction of the Reynolds shear stress.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reduced-order representation of near-wall structures in the late transitional boundary layer

et al. 2014

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“…At the wall boundary, no-slip conditions were used. The vorticity components were calculated from their relationship with velocity [19,26,27]. A buffer domain method was used at the outflow boundary to allow disturbances to travel out of the computational domain without upstream reflection.…”

Section: Simulation Of Base Flowmentioning

confidence: 99%

“…Periodicity conditions were employed at the spanwise boundaries at z = 0 and z = λ z . Centerline symmetry is not assumed here, unlike, e.g., other reported work [19,26,27], so that the asymmetric disturbance waves could develop freely.…”

Section: Simulation Of Base Flowmentioning

confidence: 99%

High Wavenumber Coherent Structures in Low Re APG-Boundary-Layer Transition Flow—A Numerical Study

Chen¹,

Lo²

2017

Fluids

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This paper presents a numerical study of high wavenumber coherent structure evolution in boundary layer transition flow using recently-developed high order Combined compact difference schemes with non-uniform grids in the wall-normal direction for efficient simulation of such flows. The study focuses on a simulation of an Adverse-Pressure-Gradient (APG) boundary layer transition induced by broadband disturbance corresponding to the experiment of Borodulin et al. (Journal of Turbulence, 2006, 7, pp. 1-30). The results support the experimental observation that although the coherent structures seen during transition to turbulence have asymmetric shapes and occur in a random pattern, their local evolutional behaviors are quite similar. Further calculated local wavelet spectra of these coherent structures are also very similar. The wavelet spectrum of the streamwise disturbance velocity demonstrates high wavenumber clusters at the tip and the rear parts of the Λ-vortex. Both parts are imbedded at the primary Λ-vortex stage and spatially coincide with the spike region and high shear layer. The tip part is associated with the later first ring-like vortex, while the rear part with the remainder of the Λ-vortex. These observations help to shed light on the generation of turbulence, which is dominated by high wavenumber coherent structures.

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“…Maekawa et al (1992) performed direct numerical simulations of the unstable two-dimensional far wake, based on the algorithm developed by Buell (1991), related to the methodology developed at the Transition and Turbulence Group, Universität Stuttgart (e.g. Rist & Fasel 1991;Kloker & Bestek 1992). The nonlinear primary flow is here, by necessity, recomputed from Maekawa et al (1992) for the desired parameter values for secondary instability studies.…”

Section: Summary Of the Nonlinear Spatial Two-dimensional Primary Wakmentioning

confidence: 99%

Three-dimensional secondary instability of a spatially developing von Kármán vortex street in a far wake

Liu

2010

Proc. R. Soc. A.

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This paper presents studies of a three-dimensional secondary instability of a spatially developing von Kármán vortex street. It develops owing to the nonlinear interaction between a two-dimensional mean far-wake flow and its most unstable disturbances. This forms a nonlinear primary wake flow. Sections of this flow are selected to perform a temporal secondary stability study under the assumption of parallel flow. The eigenvalue characteristics of the secondary instability are compared with the results from the use of a linear primary flow comprising unmodified mean wake flow coexisting with a linear primary fundamental disturbance with an empirical amplitude as a parameter, resulting in a simpler Floquet analysis. The maximum amplification rates occur at about the same spanwise wavenumber for both the nonlinear and linear primary flows, in qualitative agreement. But the amplification rate versus the spanwise wavenumber spectrum are both qualitatively and quantitatively different, the nonlinear primary flow results in a lower magnitude of the amplification rates. Some interpretations of controlled experiments are made, and it is concluded that the two-and threedimensional disturbances so obtained appeared to be from the primary instability, where the amplification mechanisms come from the unmodified mean flow. A general discussion of the nonlinear interaction between the primary two-dimensional flow and the threedimensional secondary instability is given, which may well form the basis for further nonlinear studies.

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Direct numerical simulation of controlled transition in a flat-plate boundary layer

Cited by 195 publications

References 16 publications

Reduced-order representation of near-wall structures in the late transitional boundary layer

Reduced-order representation of near-wall structures in the late transitional boundary layer

High Wavenumber Coherent Structures in Low Re APG-Boundary-Layer Transition Flow—A Numerical Study

Three-dimensional secondary instability of a spatially developing von Kármán vortex street in a far wake

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