Mechanisms and passive control of crossflow-vortex-induced transition in a three-dimensional boundary layer

Wassermann, Peter; Kloker, Markus J.

doi:10.1017/s0022112001007418

Cited by 214 publications

(284 citation statements)

References 31 publications

(51 reference statements)

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“…The initial amplitudes of the secondary instability modes for both cases in Fig.12 are equal to 0.01. The "Rib-like" structures previously observed in [19] and [21] are clearly visible in both cases. By examining the vorticity of these "ribs", it can be determined that these are, in fact, co-rotating vortices which ride on the top of the stationary crossflow vortex in the case of Y-mode, or on the side of the stationary vortex in the case of Z-mode of secondary instability.…”

Section: Nonlinear Development and Breakdown Of Secondary Instabilitysupporting

confidence: 58%

“…Furthermore, these "ribs" align themselves at an oblique angle relative to the axis of the stationary crossflow vortex (see, also, ref. [19] in this context). Farther downstream, smaller structures begin to appear, which should eventually lead to turbulence.…”

Section: Nonlinear Development and Breakdown Of Secondary Instabilitymentioning

confidence: 90%

“…However, it is also instructive to study the nonlinear evolution of the secondary mode perturbations in order to study the breakdown mechanisms responsible for the onset of transition. Wassermann and Kloker [19] carried out direct numerical simulations (DNS) of secondary instability well into the breakdown region and revealed some interesting features of the breakdown process for a specific wind tunnel configuration. Although DNS is a powerful tool, it is also costly.…”

Section: Nonlinear Development and Breakdown Of Secondary Instabilitymentioning

confidence: 99%

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Roughness Based Crossflow Transition Control: A Computational Assessment

Choudhari

Chang

et al. 2009

27th AIAA Applied Aerodynamics Conference

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A combination of parabolized stability equations and secondary instability theory has been applied to a low-speed swept airfoil model with a chord Reynolds number of 7.15 million, with the goals of (i) evaluating this methodology in the context of transition prediction for a known configuration for which roughness based crossflow transition control has been demonstrated under flight conditions and (ii) of analyzing the mechanism of transition delay via the introduction of discrete roughness elements (DRE). Roughness based transition control involves controlled seeding of suitable, subdominant crossflow modes, so as to weaken the growth of naturally occurring, linearly more unstable crossflow modes. Therefore, a synthesis of receptivity, linear and nonlinear growth of stationary crossflow disturbances, and the ensuing development of high frequency secondary instabilities is desirable to understand the experimentally observed transition behavior. With further validation, such higher fidelity prediction methodology could be utilized to assess the potential for crossflow transition control at even higher Reynolds numbers, where experimental data is currently unavailable.

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Section: Nonlinear Development and Breakdown Of Secondary Instabilitysupporting

confidence: 58%

Section: Nonlinear Development and Breakdown Of Secondary Instabilitymentioning

confidence: 90%

Section: Nonlinear Development and Breakdown Of Secondary Instabilitymentioning

confidence: 99%

See 1 more Smart Citation

Roughness Based Crossflow Transition Control: A Computational Assessment

Choudhari

Chang

et al. 2009

27th AIAA Applied Aerodynamics Conference

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“…Fischer & Dallmann (1991); Malik et al (1999); Haynes & Reed (2000); Janke & Balakumar (2000); Koch et al (2000); Koch (2002); Bonfigli & Kloker (2007)) and on numerical investigations (e.g. Högberg & Henningson (1998); Wassermann & Kloker (2002; Bonfigli & Kloker (2007)) have been performed.…”

Section: Background and Present Workmentioning

confidence: 99%

“…For more complete reviews the reader is instead referred to Bippes (1999); Arnal & Casalis (2000); Saric et al (2003) and to some more recent studies such as Wassermann & Kloker (2002; White & Saric (2005); Bonfigli & Kloker (2007); Downs & White (2013) and Hosseini et al (2013).…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional organisation of primary and secondary crossflow instability

2016

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An experimental investigation of primary and secondary crossflow instability developing in the boundary layer of a 45 • swept wing, at a chord Reynolds number of 2.17·10 6 is presented. Linear stability theory is applied for preliminary estimation of the flow stability while surface flow visualisation using fluorescent oil is employed to inspect the topological features of the transition region. Hot-wire anemometry is extensively used for the investigation of the developing boundary layer and identification of the statistical and spectral characteristics of the instability modes. Primary stationary as well as unsteady type-I (z-mode), type-II (y-mode) and type-III modes are detected and quantified. Finally, three-component, three-dimensional measurements of the transitional boundary layer are performed using tomographic particle image velocimetry. This research presents the first application of an optical experimental technique for this type of flow. Among the optical techniques tomographic velocimetry represents, to date, the most advanced approach allowing the investigation of spatially correlated flow structures in threedimensional fields. Proper orthogonal decomposition (POD) analysis of the captured flow fields is applied to this goal. The first POD mode features a newly reported structure related to low-frequency oscillatory motion of the stationary vortices along the spanwise direction. The cause of this phenomenon is only conjectured. Its effect on transition is considered negligible but, given the related high energy level, it needs to be accounted for in experimental investigations. Secondary instability mechanisms are captured as well. The type-III mode corresponds to low frequency primary travelling crossflow waves interacting with the stationary ones. It appears in the inner upwelling region of the stationary crossflow vortices and is characterised by elongated structures approximately aligned with the axis of the stationary waves. The type-I secondary instability consists instead of significantly inclined structures located at the outer upwelling region of the stationary vortices. The much narrower wavelength and higher advection velocity of these structures correlate with the higher-frequency content of this mode. The results of the investigation of both primary and secondary instability from the exploited techniques agree with and complement each other and are in line with existing literature. Finally, they present the first experimental observation of the secondary instability structures under natural flow conditions.

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The advantages of using high-order finite differences schemes in laminar-turbulent transition studies

Souza

Mendonça

Medeiros

2005

Int. J. Numer. Meth. Fluids

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SUMMARYThis paper presents various ÿnite di erence schemes and compare their ability to simulate instability waves in a given ow ÿeld. The governing equations for two-dimensional, incompressible ows were solved in vorticity-velocity formulation. Four di erent space discretization schemes were tested, namely, a second-order central di erences, a fourth-order central di erences, a fourth-order compact scheme and a sixth-order compact scheme. A classic fourth-order Runge-Kutta scheme was used in time. The inuence of grid reÿnement in the streamwise and wall normal directions were evaluated. The results were compared with linear stability theory for the evolution of small-amplitude Tollmien-Schlichting waves in a plane Poiseuille ow. Both the ampliÿcation rate and the wavenumber were considered as veriÿcation parameters, showing the degree of dissipation and dispersion introduced by the di erent numerical schemes. The results conÿrmed that high-order schemes are necessary for studying hydrodynamic instability problems by direct numerical simulation.

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Mechanisms and passive control of crossflow-vortex-induced transition in a three-dimensional boundary layer

Cited by 214 publications

References 31 publications

Roughness Based Crossflow Transition Control: A Computational Assessment

Roughness Based Crossflow Transition Control: A Computational Assessment

Three-dimensional organisation of primary and secondary crossflow instability

The advantages of using high-order finite differences schemes in laminar-turbulent transition studies

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