Numerical simulation of turbulent spots in channel and boundary layer flows

Measurements are presented of the calmed region behind triggered wave packets and turbulent spots under a controlled diffusion adverse pressure gradient in a wind tunnel. Similar measurements are also presented from the stator blades of an axial flow compressor, where turbulent spots are induced by the passing of rotor wakes. The purpose is to gain an appreciation of turbulent spot behavior under a strong adverse pressure gradient as a foundation for the more accurate modeling of spots and their environment in predictions of transitional boundary layer flows. Under an adverse pressure gradient the calmed region behind the spot is extensive; its interaction with the surrounding turbulent layer is complex and is dependent on whether the surrounding natural boundary layer is laminar or turbulent. Some insights are gleaned concerning the behavior of the calmed region which will subsequently be used in attempts to model the calmed region. Although these fundamental investigations of the calmed region have been extensive much remains to be understood.

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A numerical simulation of boundary-layer flows near shelterbelts

Boundary-Layer Meteorology ◽

10.1007/bf00721047 ◽

1995 ◽

Vol 75 (1-2) ◽

pp. 141-173 ◽

Cited By ~ 74

Author(s):

Hao Wang ◽

Eugene S. Takle

Keyword(s):

Numerical Simulation ◽

Boundary Layer ◽

Boundary Layer Flows

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Edge states as mediators of bypass transition in boundary-layer flows

Journal of Fluid Mechanics ◽

10.1017/jfm.2016.434 ◽

2016 ◽

Vol 801 ◽

Cited By ~ 20

Author(s):

T. Khapko ◽

T. Kreilos ◽

P. Schlatter ◽

Y. Duguet ◽

B. Eckhardt ◽

...

Keyword(s):

Boundary Layer ◽

Three Dimensional ◽

Discrete Symmetry ◽

Edge State ◽

Bypass Transition ◽

Computational Domain ◽

Edge States ◽

Boundary Layer Flows ◽

Turbulent Spots ◽

Edge Tracking

The concept of edge states is investigated in the asymptotic suction boundary layer in relation to the receptivity process to noisy perturbations and the nucleation of turbulent spots. Edge tracking is first performed numerically, without imposing any discrete symmetry, in a large computational domain allowing for full spatial localisation of the perturbation velocity. The edge state is a three-dimensional localised structure recurrently characterised by a single low-speed streak that experiences erratic bursts and planar shifts. This recurrent streaky structure is then compared with predecessors of individual spot nucleation events, triggered by non-localised initial noise. The present results suggest a nonlinear picture, rooted in dynamical systems theory, of the nucleation process of turbulent spots in boundary-layer flows, in which the localised edge state plays the role of state-space mediator.

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Numerical Simulation of Receptivity Phenomena in Transitional Boundary-Layer Flows

AIAA Journal ◽

10.2514/2.7448 ◽

1997 ◽

Vol 35 (5) ◽

pp. 789-795

Author(s):

Scott H. Reitsma ◽

Vincent P. Manno ◽

Thomas R. Tureaud

Keyword(s):

Numerical Simulation ◽

Boundary Layer ◽

Boundary Layer Flows ◽

Transitional Boundary Layer

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Investigation of the Calmed Region Behind a Turbulent Spot

Journal of Turbomachinery ◽

10.1115/1.2841191 ◽

1997 ◽

Vol 119 (4) ◽

pp. 802-809 ◽

Cited By ~ 14

Author(s):

J. P. Gostelow ◽

G. J. Walker ◽

W. J. Solomon ◽

G. Hong ◽

N. Melwani

Keyword(s):

Boundary Layer ◽

Pressure Gradient ◽

Axial Flow ◽

Adverse Pressure Gradient ◽

Turbulent Spot ◽

Boundary Layer Flows ◽

Turbulent Spots ◽

Controlled Diffusion ◽

Transitional Boundary Layer ◽

Flow Compressor

Measurements are presented of the calmed region behind triggered wave packets and turbulent spots under a controlled diffusion adverse pressure gradient in a wind tunnel. Similar measurements are also presented from the stator blades of an axial flow compressor, where turbulent spots are induced by the passing of rotor wakes. The purpose is to gain an appreciation of turbulent spot behavior under a strong adverse pressure gradient as a foundation for the more accurate modeling of spots and their environment in predictions of transitional boundary layer flows. Under an adverse pressure gradient the calmed region behind the spot is extensive; its interaction with the surrounding boundary layer is complex and is dependent on whether the surrounding natural boundary layer is laminar or turbulent. Some insights are gleaned concerning the behavior of the calmed region, which will subsequently be used in attempts to model the calmed region. Although these fundamental investigations of the calmed region have been extensive, much remains to be understood.

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