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Mr. Javidan Ahmad May 12, 2005 12:26

Selecting Wall Cells for Drag Force
I am currently investigating the aerodynamics of a motorcycle. The Geometry was created in Pro-Engineer and using Pro-Am manipulation, resulted in obtaining a domain with a hollow centre - where the hollow centre represents the wall of the bike.

However, in order to obtain the Drag force on the motorcycle i am required to select the surface cells which are on the motorcycle.

Currently, using the typical procedures (selcting cells, zones, based on edges etc) it is too time consuming and cumbersome to select the cells as a separate wall boundary.

It is required to select the wall surfaces of the motorcycle as a separate wall boundary as the default wall boundary (boundary region 0 - zero) does not allow the selection of forces in the monitor boundary behaviour menu (Analysis Controls>output controls>monitor engineering b>monitor boundary behaviour)

If anyone can advise me on what steps i can take to select the cells i require or any other method of working out the drag i would extremely appreciative.

Kind regards, Mr.Javidan Ahmad.

Ant May 12, 2005 20:59

Re: Selecting Wall Cells for Drag Force
If you have any shell-type cells, you can always convert them in any boundaries! Look at the command "bshell,....."

Javidan Ahmad May 13, 2005 10:31

Re: Selecting Wall Cells for Drag Force
Dear Ant,

1.Thank you very much for your help.

2. I have had a look a the BSHELL command, and as far as i can see in order to use this command i require shell-cells on the boundary at which i intend to monitor the Drag force. However, due to the manner in which Pro-Am creates the Fluid Cells, there are no Shell cells at the location of the hollow centre (i.e bike geometry).

3. If anyone has any other suggestions please post a reply.

Kind regards, Javidan Ahmad.

Ant May 13, 2005 22:20

Re: Selecting Wall Cells for Drag Force
You can create shell cells using Pro*am! Use the panel Generate Mesh->Extrusion Layer, in which activate the CREATE SURFACE TO EXTRUDE radio button! Then use the Method as Entire Surface and push the button Create Surface! As a result you get a shells around all outside surfaces to the fluid cells! Now you have to separate unnecessary shells using typical commands of Prostar or Pro*am! And what is your aim? Monitoring forces at the time of computing or integrating the obtained results?

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