On two-dimensional gas expansion for pressure-gradient equations of Euler system

Numerical simulations of Navier–Stokes equations are performed to study the flow originated by an oscillating pressure gradient close to a wall characterized by small imperfections. The scenario of transition from the laminar to the turbulent regime is investigated and the results are interpreted in the light of existing analytical theories. The ‘disturbed-laminar’ and the ‘intermittently turbulent’ regimes detected experimentally are reproduced by the present simulations. Moreover it is found that imperfections of the wall are of fundamental importance in causing the growth of two-dimensional disturbances which in turn trigger turbulence in the Stokes boundary layer. Finally, in the intermittently turbulent regime, a description is given of the temporal development of turbulence characteristics.

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Flow Over a Cylinder at a Plane Boundary—A Model Based Upon (k–ε) Turbulence

Journal of Fluids Engineering ◽

10.1115/1.3243661 ◽

1989 ◽

Vol 111 (4) ◽

pp. 414-419 ◽

Cited By ~ 6

Author(s):

T. Solberg ◽

K. J. Eidsvik

Keyword(s):

Pressure Gradient ◽

Coordinate System ◽

Adverse Pressure Gradient ◽

Plane Boundary ◽

Length Scale ◽

Two Dimensional ◽

Curvilinear Coordinate System ◽

Recirculating Flow ◽

Model Based ◽

Curvilinear Coordinate

A model for two-dimensional flows over a cylinder at a plane boundary is developed. The model, based upon a (k-ε) turbulence closure, is formulated in a curvilinear coordinate system based upon frictionless flow. A length scale modification in areas of adverse pressure gradient and recirculating flow appears to be more realistic than the standard (k-ε) model. The main features of the predicted flow do not depend critically upon the details of the grid or model, which means that a well defined solution is obtained. The solution appears to be reasonable and validated to the extent that the data permits.

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3D Stability and Receptivity of Two-Dimensional Self-Similar Boundary Layer with Adverse Pressure Gradient

Laminar-Turbulent Transition ◽

10.1007/978-3-662-03997-7_88 ◽

2000 ◽

pp. 571-576

Author(s):

Y. S. Kachanov ◽

D. B. Koptsev ◽

B. V. Smorodskiy

Keyword(s):

Boundary Layer ◽

Pressure Gradient ◽

Adverse Pressure Gradient ◽

Two Dimensional ◽

Self Similar

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Influence of two-dimensional roughness element on boundary layer structure in the favourable pressure gradient region of the swept wing

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410019841776 ◽

2019 ◽

Vol 234 (1) ◽

pp. 20-27

Author(s):

Stepan Tolkachev ◽

Victor Kozlov ◽

Valeriya Kaprilevskaya

Keyword(s):

Boundary Layer ◽

Pressure Gradient ◽

Layer Structure ◽

Roughness Element ◽

Three Dimensional ◽

Two Dimensional ◽

Frequency Range ◽

Swept Wing ◽

Boundary Layer Structure ◽

Roughness Elements

In this article, the results of research about stationary and secondary disturbances development behind the localized and two-dimensional roughness elements are presented. It is shown that the two-dimensional roughness element has a destabilizing effect on the disturbances induced by the three-dimensional roughness element lying upstream. In this case, the two-dimensional roughness element causes the appearance of stationary structures, and then secondary perturbations, whose frequency range lies lower than in the case of the stationary vortices excited by a three-dimensional roughness element.

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Buoyant convection from horizontal surfaces at const ant pressure

Journal of Fluid Mechanics ◽

10.1017/s0022112075001851 ◽

1975 ◽

Vol 68 (3) ◽

pp. 609-624 ◽

Cited By ~ 4

Author(s):

S. C. Traugott

Keyword(s):

Pressure Gradient ◽

Boundary Layers ◽

Line Source ◽

Leading Edge ◽

Wall Jet ◽

Two Dimensional ◽

Buoyant Plume ◽

Grashof Number ◽

Buoyancy Driven Flows ◽

Streamwise Pressure Gradient

A two-dimensional horizontal flow is discussed, which is induced by other, buoyancy-driven flows elsewhere. It is an adaptation of the incompressible wall jet, which is driven by conditions a t the leading edge and has no streamwise pressure gradient. The relation of this flow to the classical buoyancy-driven boundary layers on inclined and horizontal surfaces is investigated, as well as its possible connexion with a two-dimensional buoyant plume driven by a line source of heat. Composite flows are constructed by patching various such solutions together. The composite flows exhibit$Gr^{\frac{1}{4}}$scaling (Grbeing the Grashof number).

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