CFD Tutorials

Geometry Creation

4: CFD Tutorials

4.1: Geometry Creation

4.1.1: 2D Pipe Junction

Overview

We are going to create geometry for a two-dimensional pipe junction as shown in the figure below.

Figure4-1 2D Pipe Junction with Dimensions

ANSYS ICEM CFD 11.0 Tutorial Manual

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http://www.ara.bme.hu/~lohasz/ICEM_tut/tut_1/2dpipe_geom.pdf

Geometry Creation

a) Summary of steps

Geometry Menu

Creating the points using Explicit Coordinates

Creating the points using Curve-Curve Intersection

Creating the curves using From Points

Creating the curves using Arc through 3 points

Segmentation of curve using Segment Curve

Deleting unused entities

Creating Material Point using Mid Point

File Menu

Saving the geometry

b) Point Creation

Note:

1. Settings > Selection >Auto pick mode should be turned OFF.

2. Settings>Geometry Options>Name new geometry must be turned ON.

3. Settings>Geometry Options>Inherit Part name>Create new must betoggled ON

4. In case UNDO is used after creation of any point, and then a new pointis created, the new point will have the next name in series. For example, if Point05 is created and Undo is used, then the next point created will be named Point06.

Select Geometry Create Point

x

> Explicit Coordinates

xx

> Select Create 1 Point. Input the Part name POINTS and Name as POINT 00.Assign coordinates (0 0 0) shown below. Press Apply to create a point.


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Geometry Creation

Figure 4-2 Point creation window

Switch ON the Geometry > Points in the left side Display Tree window. To see the names of the points, use the right mouse button and select Points > Show Point Names in the Display Tree window. Select Fit Window from the main menu. Use the right mouse button to zoom out if needed. The created point name would be shown as POINT00.

Now enter the coordinates as shown below, and press Apply after each one. You will see the names automatically change to the ones shown below:

POINT01 (32, 0, 0)

POINT02 (0, 16, 0)

POINT03 (32, 16, 0)

POINT04 (48, 32, 0)


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Geometry Creation

POINT05 (48, 64, 0)

POINT06 (64, 32, 0)

POINT07 (64, 64, 0)

POINT08 (50, -5, 0)

POINT09 (54, -5, 0)

POINT10 (16, 32, 0)

POINT11 (0, 32, 0)

POINT12 (50, 16, 0)

POINT13 (54, 16, 0)

Figure 4-3 Points created thus far


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Geometry Creation

Press Dismiss to close the window. Go to View > Front. The Display window should now show the points as seen in the figure above. The location of points can also be checked by following way –Go to Utility

Icons > Click on the inverted arrow below Measure distance icon

>Last option is Find Location

xx

Select any point on screen. The Co-Ordinates of the point will be shown on screen as well as will be visible in the Message Window.

c) Line Creation

reate odify Curve

Geometry > C /M

x

> From Points: Select the From

oints option

x

P .

Figure 4-4 : From points window


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Geometry Creation

To select Points, click on (select point icon) and then select POINT00 and POINT01 with the left mouse button. Press the middle mouse button to accept the points. The point names will appear in the selection window. Enter the Part as CURVES, and the Name as CURVE00. Switch ON Geometry > Curvesin the Display Tree if they are switched off. To see the names of the curves, use the right mouse button and select Curves > Show Curve Names in the Display Tree. Use the right mouse button to zoom out if needed. The created line name would be shown as CURVE00.

imilarly, select the following points, pressing S middle mouse button each y default the names of each ft:

T012 URVE08 from POINT09 and POINT013

he window.

eometry > Create/Modify Curves

time. Without changing the Name entry, bnew curve would appear as shown on the le CURVE01 from POINT00 and POINT02 CURVE02 from POINT02 and POINT03 CURVE03 from POINT04 and POINT05 CURVE04 from POINT05 and POINT07 CURVE05 from POINT06 and POINT07

T09 CURVE06 from POINT08 and POINURVE07 from POINT08 and POINC

CPress Dismiss to close t

d) Arc Creation

x

G > Select Arc Through 3 points

xx

to open the window here.


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Geometry Creation

Figure 4-5 Arc from 3 points window

To select Points click on (select point icon), and select the points POINT04, POINT03 and POINT10 with the left mouse button. Press the middle mouse button to accept the point. Click on the drop down menu next to the Part field to select an existing Part Click on CURVES to select this Part in the window. Enter the Name as CURVE09 and press Apply to create the arc. Similarly, make another arc named CURVE10 out of points POINT06, POINT01, and POINT11. Press Dismiss to close this window. The eometry after creating the two arcs is shown here. g

Figure 4-6 Geometry after arc creation


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Geometry Creation

e) Curve-Curve Intersection

Geometry >Create Point

x

> Select Curve-Curve Intersection

x

thewindow opens as shown below. Select the Part name POINTS. Select CURVE10 and CURVE07 with the left mouse button. Press the middlemouse button to accept the selection. Give Gap a Tolerance of 0.1 and press Apply. This will create the intersection point called POINT14. Repeat the procedure for curves CURVE10 and CURVE08 and press


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Geometry Creation

Apply without changing the name in the Name window to get the intersection point POINT15. Press Dismiss to close the Create Point window.

Figure 4-7 Selection window of Curve-Curve Intersection

f) Segmentation of Curves at existing points

Geometry > Create/Modify Curve

x

> Select Segment curve

x

. In the dropdown, Segment by Point should be selected. Select the cur

selection icon

ve

x

and select CURVE10 with the left mouse button.

Now select the point selection icon and select POINT01 with the left mouse button and then press the middle mouse button to accept the point. Select the Part CURVES .After pressing Apply, the CURVE10 segments into two curves, CURVE10 and CURVE11.


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Geometry Creation


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er segmenting two Curves at a particular Point the Curves name may be ifferent but user can refer to the figure below and select the Curves to be eleted.

Figure 4-8 Geometry after curve segmentations

Similarly segment CURVE09 at POINT03 to get CURVE09 and CURVE12. Segment CURVE07 at POINT14 to get CURVE07 and CURVE13. Segment CURVE08 at POINT15 to get CURVE08 and CURVE14. The geometry after segmenting the curve is shown below.

Note: Aftdd

Geometry Creation

g) Deletion of unused entities

Geometry > Delete Curve

x

- This will open the Delete Curve window.

Select the curve selection icon

x

and select CURVE11, CURVE12, CURVE13 and CURVE14. Press the middle mouse button to complete the selection. Press Applyto delete these curves.


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Geometry Creation


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Geometry >Delete Points

x

This will open the Delete Points window.

Select the point selection icon and select POINT10, POINT11, POINT12 and POINT13. Press the middle mouse button to complete selection, and press Apply to delete these points.

h) Creating the Material point

Geometry > Create Body >

x

Material Point > Centroid of 2

points: Select the location selection icon and click close to POINT01 and POINT03 with the left mouse button. Press the middle mouse button to complete the selection. Give the Part name BODY, and press Apply to create the material point. Switch on Bodies in the left side Display Tree window to see the body. The Geometry after creating material point is shown below. Figure 4-9 Final Geometry

Geometry Creation

i) Saving Geometry

File > Geometry > Save Geometry As: Enter the file name as Geo_2DPipe.tin and press Save to save the geometry file


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