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WORKSHOP - Simulation of a Flow between cylindrical obstacles.

Object Arraying

This workshop example shows how to use the Object Arraying facility of the VR Editor. The flow is two-dimensional and its geometry is shown in the figure below. The shaded circles represent cylinders. Velocity and pressure will be solved.

Accessing PHOENICS-VR.

From the system level:

To enter the PHOENICS-VR environment, click on the PHOENICS icon on the desktop, or click on Start, programs, PHOENICS, PHOENICS.

In PHOENICS-VR environment,

Start with an 'empty' case - click on 'File' then on 'Start New Case', then on 'Core', then click on 'OK' to confirm the resetting.

To enter VR Editor:

This is the default mode of operation.

Within VR Editor.

Set the domain size and activate solution of required variables:

Click on 'Main Menu' and set 'Flow between cylinderical obstacles' as the Title.

Click on 'Geometry'.

Change the X-domain Size to 2.0 m.

Click 'OK' to close the Grid mesh settings dialog.

Click on 'Models'.

Leave the 'solution for velocities and pressure' ON.

Select 'Laminar' from 'Turbulence models'.

Click on 'Top menu', then on 'OK'.

Click on 'Reset' button on the movement control panel and then click on 'Fit to window'/'OK'.

 

Introduce the required objects

Create the fluid inlet:

In the Object-management dialog, click on 'Object', 'New' and 'New Object' to bring up the object specification dialog box.

Change name to INLET.

Click on 'Size' and set SIZE of object as:

Xsize: 0.0

Ysize: tick 'To end'

Zsize: 0.5

Click on 'Place' and set POSITION of object as:

Xpos: 0.0

Ypos: 0.0

Zpos: 0.25

Click on 'General'.

Define Type: Inlet

Click on 'Attributes' and set velocity in X-direction at 0.1 m/s.

Click on 'OK' to close the Attribute menu, and on 'OK' in the Object Dialogue Box.

 

Create the fluid outlet:

'Object', 'New' and 'New Object'.

Change name to OUTLET.

Click on 'Size' and set SIZE of object as:

Xsize: 0.0

Ysize: tick 'To end'

Zsize: 0.5

Click on 'Place' and set POSITION of object as:

Xpos: tick 'At end'

Ypos: 0.0

Zpos: 0.25

Click on 'General'.

Define Type: Outlet.

Leave the default values in the 'Attributes' dialogue box.

Click on 'OK' to exit from the Object Dialogue Box.

 

Create the first cylinder:

Click on 'Settings', 'New' and 'New Object'.

Change name to CYL-1 (which stands for cylinder 1).

Click on 'Size' and set SIZE of object as:

Xsize: 0.15

Ysize: tick 'To end'

Zsize: 0.15

Click on 'Place' and set POSITION of object as:

Xpos: 0.4

Ypos: 0.0

Zpos: 0.25

Click on 'Shape'.

In 'Geometry', select /public/SHAPES/CYLINDER and click on 'Save'.

Click on 'Options' and 'ROTATION options', then  click on the ^ button beside 'Rotate object face' until the cylinder is aligned as in the earlier diagram (this should be at position 5). We are working through the 24 possible ways of placing a shape into a box until we find the right one.

Click on 'OK'.

Define Type: Blockage (default).

Leave the default values in the Attributes menu.

Click on 'OK' to close the Object Dialogue Box.

 

Create the remaining cylinders by copying from CYL-1. We want 3 cylinders in the X direction, with a 0.5m space between them, and 2 in Z, spaced at 0.35m.

Check that the original cylinder is still selected and appears with white high-lighting, if not click on it, then on OK.

Now click on the 'Duplicate using array' button on the handset. It has this icon: Duplicate using array

In the new dialogue box, set

Direction Dimension Pitch
X 3 0.5
Y 1 0.0
Z 2 0.35

Click on 'OK' to exit the dialogue box.

An array of cylinders appears in the domain.

 

Set the grid:

Click on the 'Mesh toggle' button. The default mesh (shown as blue and orange lines) will appear on the screen. The orange lines are 'regions', defined by the bounding boxes of the objects. This mesh (39 in X, 20 in Z) is adequate for this tutorial.  Click on 'Mesh toggle' again to turn off the mesh display.

 

Set the remaining solution control parameters:

Click on 'Main Menu' and then on 'Numerics'.

Set the number of iterations to 200.

Click on 'Top menu' to return to the top menu.

Click on 'OK' to exit the Main Menu.

 

Running the Solver.

In the PHOENICS-VR environment, click on 'Run', 'Solver'(Earth), and click on 'OK'; to confirm running Earth.

 

Using the VR Viewer.

In the PHOENICS-VR environment, click on 'Run', 'Post processor',then GUI Post processor (VR Viewer) . Click 'OK' on the file names dialog to accept the default files.

To view:

To select the plotting variable:

To change the direction of the plotting plane, set the slice direction to X, Y or Z slice direction (927 bytes)

To change the position of the plotting plane, move the probe using the probe position buttons

probe position (927 bytes).

A typical plot from this case is:

 

Saving the results.

In the PHOENICS-VR environment, click on 'Save as a case', make a new folder called 'COLUMNS' (e.g.) and save as 'CASE1' (e.g.).