ansys-cfd流体分析实例

Example on using commercial software

“ICEM CFD 5.1”

Flow around a circular cylinder

Y.F.Lin

Two Dimensional problems

Flow around a circular cylinder

Problem Description

Air flows across a cylinder with the uniform velocity 0.003m/s in the wind tunnel. The length of the wind tunnel (fluid domain) has 25m long and 10 m height. The diameter of cylinder is 1m .

Assumption and Boundary Conditions:

1. 2 dimensional problems

2. Steady state condition

3. The uniform flow velocity

4. No Heat transfer

5. Neglect the gravitational force

6. Constant air density

Pre-processing stage

In this stage, we implement the “ICEM CFD” to perform the pre-processing work. The basic steps as follow:

1. Establish geometry model

2. Block the parts

3. Generation the O grid

4. Mesh the model and check quality of mesh

5. Extrude the mesh

6. Reset the BC’s (boundary conditions)

7. Output to CFX5.7.1

Creating Geometry

1. Open ICEM CFD

Outlet

Wall (SideA)

Double Click the “ICEM CFD” Icon, afterwards, you can see the interface of the ICEM CFD.

Open File>New Project…:

Set the name with “cylinder_2d”, and Click “Save”

2. Creating Geometry:

A.Points

Click button “Create Point” and then click button “Explicit Coordinates”

Set the points in Cartesian coordinate system(X, Y, Z) with ( X=0, Y=0, Z=0 ) respectively.

Click “Apply” button and see the screen: a point is created

A tree widget can be seen at left of the screen (A) and (B)

A B

The same method creates other points:

X=0; Y=0.5, -0.5 X=-5; Y=5, -5

X=20; Y=5, -5 Y=0; X=0.5,-0.5

B.Draw line (curve)

First of all see the tree widget, open Model>Geometry>Points by right button

Select Show Point Names and you can see the name of each point like the figure showed.