scholarly journals On two-dimensional Riemann problem for pressure-gradient equations of the Euler system

1998 ◽  
Vol 4 (4) ◽  
pp. 609-634 ◽  
Author(s):  
Peng Zhang ◽  
◽  
Jiequan Li ◽  
Tong Zhang ◽  
◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Riemann Problem ◽  
Euler System ◽  
Two Dimensional ◽  
Pressure Gradient Equations

New Pressure Gradient Equations for Lumped-Parameter Interior Ballistic Codes

1990 ◽  
Author(s):  
Frederick W. Robbins ◽  
Ronald D. Anderson ◽  
Paul S. Gough
Keyword(s):  
Pressure Gradient ◽  
Lumped Parameter ◽  
Pressure Gradient Equations

Direct simulation of transition in an oscillatory boundary layer

1998 ◽  
Vol 371 ◽  
pp. 207-232 ◽  
Author(s):  
G. VITTORI ◽  
R. VERZICCO
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Turbulent Regime ◽  
Two Dimensional ◽  
Temporal Development ◽  
Direct Simulation ◽  
Navier Stokes Equations ◽  
Oscillatory Boundary Layer

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.

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

1989 ◽  
Vol 111 (4) ◽  
pp. 414-419 ◽  
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.

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

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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