CFX-4
Introductory Training (Dec 1999)
2-1
CFX-4.3 V4.3.1H
Lecture 2
Geometry Creation
几何构体
CFX-4
Introductory Training (Dec 1999)
2-2
CFX-4.3 V4.3.1H
Multi-block Grids
? The geometry is a set of hexahedral solids
which have a logical representation.
? Each block in the geometry is called a ‘solid’.
? Each solid in the geometry can represent a
fluid,porous or solid region.
CFX-4
Introductory Training (Dec 1999)
2-3
CFX-4.3 V4.3.1H
Multi-block -Connections
? Solids which meet at whole faces are
automatically connected.
? If solids meet where one face is adjacent to
part of another,constraints must be used to
define the interface connection.
? 约束条件
? Constraints are used to obtain a consistent
grid.
CFX-4
Introductory Training (Dec 1999)
2-4
CFX-4.3 V4.3.1H
Multi-block Concept
? Multi-block:
Multiple blocks joined to form the flow domain.
Each block has 6 faces,8 vertices,12 edges.
Structured grid for each block.
Each block is composed of cells
> 2D - cells form a rectangular array
> 3D - cells form a cuboidal array.
CFX-4
Introductory Training (Dec 1999)
2-5
CFX-4.3 V4.3.1H
T-Junction Example
CFX-4
Introductory Training (Dec 1999)
2-6
CFX-4.3 V4.3.1H
Square to Circular Duct Example
CFX-4
Introductory Training (Dec 1999)
2-7
CFX-4.3 V4.3.1H
The Power of Multi-Block
? Use fewer cells,less memory and CPU time.
Single block Two blocks
CFX-4
Introductory Training (Dec 1999)
2-8
CFX-4.3 V4.3.1H
The Power of Multi-Block
? Reduce cell distortion,makes the solution
more accurate.
One block Five blocks
CFX-4
Introductory Training (Dec 1999)
2-9
CFX-4.3 V4.3.1H
The Power of Multi-Block
? Local mesh refinement.
CFX-4
Introductory Training (Dec 1999)
2-10
CFX-4.3 V4.3.1H
The Power of Multi-Block
? Complex shape / structure.