gambit网格加密技巧.pdf

文档介绍：GAMBIT Tips and Tricks
Sizing Functions and
Boundary Layers
Roopesh Mathur
June 8, 2004
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Agenda
ƒ Introduction to Sizing Functions and Boundary Layers
ƒ Sizing Functions
ƒ Boundary Layers
ƒ New features and improvements in GAMBIT
ƒ Meshing strategies using sizing functions and boundary layers
ƒ Summary
ƒ Resources and References
ƒ Appendix
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Introduction to Sizing Functions and Boundary
Layers
ƒ What are Sizing Functions and Boundary Layers?
ƒ Sizing Functions and Boundary Layers are mesh control tools in GAMBIT for
growing mesh in geometry.
ƒ Sizing functions can be used to smoothly control the growth in mesh size over
any particular region of the geometry or the entire geometry, starting from a
“source” or origin.
ƒ Sizing functions are used to smoothly transition from fine mesh needed to
resolve flow physics to coarser mesh, resolve curvature and thin gaps.
ƒ Boundary layers are used to grow a small number of layers of cells of desired
height from particular boundaries of 2-D/3-D geometry and are used to
capture near wall phenomena such as turbulence.
Fixed size
function used
to grade quad
Boundary layer grown
pave mesh
from airfoil surface to
away from
capture for near wall
airfoil surface
phenomena
Low Speed Airfoil
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Traditional Unstructured Meshing
ƒ The size and rate of growth of the mesh elements inside the face/volume are
determined by the algorithm and the user specified edge/face meshes only.
ƒ Most algorithms have parameters for users to tweak and refine the inside
mesh generation but only in a limited way
ƒ No effective and direct user control over how the unstructured meshes inside
the face or volume are to be generated.
User Specified Edge Face Meshing Face Mesh
Mesh Tools
Face Mesh
Volume Meshing
Algorithm Volume Mesh
Boundary Layer
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Unstructured Meshing with Sizing Function and
Boundary Layers
ƒ Sizing Funct