The dynamics of coherent structures in a flat-plate boundary layer

1993 ◽  
Vol 51 (1-2) ◽  
pp. 73-77 ◽  
Author(s):  
D. Rempfer ◽  
H. Fasel
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Coherent Structures ◽  
Plate Boundary ◽  
Flat Plate Boundary Layer

scholarly journals Visualization of coherent structures in a supersonic flat-plate boundary layer

2011 ◽  
Vol 56 (6) ◽  
pp. 489-494 ◽  
Author(s):  
Lin He ◽  
ShiHe Yi ◽  
YuXin Zhao ◽  
LiFeng Tian ◽  
Zhi Chen
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Coherent Structures ◽  
Plate Boundary ◽  
Flat Plate Boundary Layer

Dynamics of three-dimensional coherent structures in a flat-plate boundary layer

1994 ◽  
Vol 275 ◽  
pp. 257-283 ◽  
Author(s):  
Dietmar Rempfer ◽  
Hermann F. Fasel
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Coherent Structures ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Galerkin Projection ◽  
Power Budget ◽  
Energy Flows ◽  
Flat Plate Boundary Layer

An investigation is presented that analyses the energy flows that are connected to the dynamical behaviour of coherent structures in a transitional flat-plate boundary layer. Based on a mathematical description of the three-dimensional coherent structures of this flow as provided by the Karhunen–Loève procedure, energy equations for the coherent structures are derived by Galerkin projection of the Navier–Stokes equations in vorticity transport formulation onto the corresponding basis of eigenfunctions. In a first step, the time-averaged energy balance – showing the energy flows that support the different coherent structures and thus maintain the fluctuations of the velocity field – is considered. In a second step, the instantaneous power budget is investigated for the particularly interesting case of a coherent structure providing a prime contribution to the characteristic spike events of the transitional boundary layer. As this structure shows a strong variation in energy, the question about which mechanisms cause these variations is addressed. Our results show that the occurrence of a spike must be attributed to an autonomous event and cannot be interpreted as just an epiphenomenon of the passage of a Λ-vortex.

Coherent Structures in Transition of a Flat-Plate Boundary Layer at Ma = 0.7

2007 ◽  
Vol 24 (1) ◽  
pp. 147-150 ◽  
Author(s):  
Zhou Ying ◽  
Li Xin-Liang ◽  
Fu De-Xun ◽  
Ma Yan-Wen
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Coherent Structures ◽  
Plate Boundary ◽  
Flat Plate Boundary Layer

Evolution of three-dimensional coherent structures in a flat-plate boundary layer

1994 ◽  
Vol 260 ◽  
pp. 351-375 ◽  
Author(s):  
Dietmar Rempfer ◽  
Hermann F. Fasel
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Coherent Structures ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Complete Information ◽  
Dynamical Behaviour ◽  
Higher Order ◽  
Temporal Behaviour ◽  
Flat Plate Boundary Layer

Using a data base generated by a numerical simulation, the three-dimensional coherent structures of a transitional, spatially evolving boundary layer are determined and their spatio-temporal behaviour is investigated in detail. The coherent structures are calculated by the proper orthogonal decomposition method (POD), which leads to an expansion of the flow field variables into Karhunen-Loéve eigenfunctions. It is shown that the dynamical coherent structures of the flat-plate boundary layer can be described by pairs of eigenfunctions that contain complete information on the spatial evolution of the structures. It is further demonstrated that first-order coherent structures determined by POD correspond to structures that are observed in experiments. In the region of the boundary layer where the spike signals of transition occur, higher-order coherent structures also play an essential role. By considering these higher-order structures as well as their dynamical behaviour in time, a compact description of the flow phenomena in the boundary layer can be obtained. The description of the events occurring at the spike stages of the transitional boundary layer shows, from a coherent structures point of view, striking similarities to the bursting event of fully turbulent boundary layers.

Interaction of intersecting shocks with a flat-plate boundary layer in the presence of an entropy layer

2013 ◽  
Vol 48 (5) ◽  
pp. 636-647 ◽  
Author(s):  
V. Ya. Borovoy ◽  
I. V. Egorov ◽  
V. E. Mosharov ◽  
V. N. Radchenko ◽  
A. S. Skuratov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Plate Boundary ◽  
Entropy Layer ◽  
Flat Plate Boundary Layer

scholarly journals A Theory for Wake-Induced Transition

1989 ◽  
Author(s):  
R. E. Mayle ◽  
K. Dullenkopf
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Flow ◽  
Flat Plate ◽  
Free Stream ◽  
Plate Boundary ◽  
Transition Model ◽  
Model Comparisons ◽  
Turbulent Wakes ◽  
Flat Plate Boundary Layer

A theory for transition from laminar to turbulent flow as the result of unsteady, periodic passing of turbulent wakes in the free stream is developed using Emmons’ transition model. Comparisons made to flat plate boundary layer measurements and airfoil heat transfer measurements confirm the theory.

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