Far-field computational boundary conditions for three-dimensional external flow problems

1996 ◽  
Author(s):  
A. Verhoff
Keyword(s):  
Boundary Conditions ◽  
Three Dimensional ◽  
External Flow ◽  
Far Field ◽  
Flow Problems

Far-field computational boundary conditions for two-dimensional external flow problems

AIAA Journal ◽  
1992 ◽  
Vol 30 (11) ◽  
pp. 2585-2594 ◽  
Author(s):  
A. Verhoff ◽  
D. Stookesberry ◽  
S. Agrawal
Keyword(s):  
Boundary Conditions ◽  
External Flow ◽  
Far Field ◽  
Two Dimensional ◽  
Flow Problems

Linearized no-slip boundary conditions at a rough surface

2013 ◽  
Vol 737 ◽  
pp. 349-367 ◽  
Author(s):  
Paolo Luchini
Keyword(s):  
Aspect Ratio ◽  
Boundary Conditions ◽  
Solid Wall ◽  
Stokes Problem ◽  
Far Field ◽  
Slip Boundary Conditions ◽  
Transition Prediction ◽  
Slip Boundary ◽  
Flow Problems ◽  
Field Behaviour

AbstractLinearized boundary conditions are a commonplace numerical tool in any flow problems where the solid wall is nominally flat but the effects of small waviness or roughness are being investigated. Typical examples are stability problems in the presence of undulated walls or interfaces, and receptivity problems in aerodynamic transition prediction or turbulent flow control. However, to pose such problems properly, solutions in two mathematical distinguished limits have to be considered: a shallow-roughness limit, where not only roughness height but also its aspect ratio becomes smaller and smaller, and a small-roughness limit, where the size of the roughness tends to zero but its aspect ratio need not. Here a connection between the two solutions is established through an analysis of their far-field behaviour. As a result, the effect of the surface in the small-roughness limit, obtained from a numerical solution of the Stokes problem, can be recast as an equivalent shallow-roughness linearized boundary condition corrected by a suitable protrusion coefficient (related to the protrusion height used years ago in the study of riblets) and a proximity coefficient, accounting for the interference between multiple protrusions in a periodic array. Numerically computed plots and interpolation formulas of such correction coefficients are provided.

Two and Three-Dimensional Flow using Finite Elements

1969 ◽  
Vol 73 (707) ◽  
pp. 961-964 ◽  
Author(s):  
J. H. Argyris ◽  
G. Mareczek ◽  
D. W. Scharpf
Keyword(s):  
Finite Elements ◽  
Boundary Conditions ◽  
Stream Function ◽  
Three Dimensional ◽  
Finite Domain ◽  
Flow Problems ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Triangular Elements ◽  
Compressibility Effects

The method of finite elements is in certain cases advantageous when dealing with flow problems in a finite domain. This is particularly so when attempting to include subcritical compressibility effects. In the present note we first consider the two-dimensional flow using TRIC and TRIM-like triangular elements in conjunction with the concept of the stream function, which is assigned to the nodal points of the elements. The application of the stream function allows a direct and exact satisfaction of the boundary conditions. Strictly the elements in question could also be used in conjunction with the potential function but the observance of the boundary conditions is then cumbersome.

scholarly journals Global artificial boundary conditions for computation of external flow problems with propulsive jets

1999 ◽  
Author(s):  
Semyon Tsynkov ◽  
Saul Abarbanel ◽  
Jan Nordstrom ◽  
Victor Ryaben'kii ◽  
Veer Vatsa
Keyword(s):  
Boundary Conditions ◽  
External Flow ◽  
Artificial Boundary ◽  
Artificial Boundary Conditions ◽  
Flow Problems

Second-order, far-field computational boundary conditions for inviscid duct flow problems

AIAA Journal ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 1268-1276 ◽  
Author(s):  
A. Verhoff ◽  
D. Stookesberry
Keyword(s):  
Boundary Conditions ◽  
Second Order ◽  
Far Field ◽  
Duct Flow ◽  
Flow Problems

A numerical investigation of the influence of yarn-level finite-element model on energy absorption by a flexible-fabric armour during ballistic impact

2008 ◽  
Vol 222 (4) ◽  
pp. 259-276 ◽  
Author(s):  
M Grujicic ◽  
G Arakere ◽  
T He ◽  
M Gogulapati ◽  
B A Cheeseman
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Element Model ◽  
Far Field ◽  
Field Boundary ◽  
Fem Model ◽  
Energy Absorbing ◽  
The Impact ◽  
Textile Fabric

A series of transient non-linear dynamic finite-element method (FEM) analyses pertaining to the interaction of a single-ply plain-woven balanced square textile-fabric armour with a spherical steel projectile is carried out in order to compare the corresponding results obtained for two different yarn models: (a) a solid FEM model in which the warp and weft yarns are represented using first-order three-dimensional solid elements and (b) a membrane model in which the same yarns are represented using second-order membrane elements. The analyses are carried out under different yarn—yarn and projectile—fabric frictional conditions and under different far-field boundary conditions applied to the edges of the fabric. The results obtained showed that the two sets of analyses yield comparable predictions regarding the temporal evolution and the spatial distribution of the deformation and damage fields within the fabric, regarding the ability of the fabric to absorb the projectile's kinetic energy and regarding the relative contributions of the main energy absorbing mechanisms. The work also confirmed the roles yarn—yarn and projectile—fabric friction play in the impact process as well as the effect of the far-field boundary conditions applied to the edges of the fabric.

Sign in / Sign up

Export Citation Format

Share Document