CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CD-adapco (
-   -   How to do this? (

Lee June 4, 2003 19:28

How to do this?
I am a new user of STAR-CD. I want to compute a simple model(A),A has three boundary regions:inlet,pressure and wall.The initial data of inlet boundary of A must be gotten from the other model(B). I plan to compute B first,then I get the data needed by A from B. But how can I get these data from B to A? What works do I need to do in order to realize this goal? Do I use the subroutines? As I know,the velocity of U,V,W in inlet boundary aren't arrays,so how can I get the velocities from B to A?

Please give me the detail answers.

Thank you very much!


Sunlight007 June 5, 2003 13:14

Re: How to do this?
Try to make two blocks(A and B) of model C. You can color them differently for e.g. At end of A, B follows. Getting the values at end of A: 1) cell color 1: get data at geometric end of A or you could make use of so called sensor points 2) it would be interesting if the solution is same if you first only calculate A, get data at end (sensor points) and use it in user subroutine BCDEFI (this you do by first creating directory ufile in same directory where your star session runs). Hope it helps

Lee June 6, 2003 05:17

Re: How to do this?
Thank you very much,sunlight007! I really want to know how to transfer the data from one of the regions of one model(A) to the inlet boundary region of the other model(B).Need I compile a command file which will be executed in order to get the data from model A and then put the data into the inlet boundary of model B? For instance,I want to get the velocities of model A,then I transfer this velocitiy data to the inlet boundary region of model B.But in user subroutines BCDEFI,the U,V,W are not arrays,how can I give the data to every cell of the inlet region of model B?

Your help is very grateful!


Sunlight007 June 6, 2003 08:01

Re: How to do this?
I am unclear what you want: are Aand B disconnected blocks? Then reconsider why you want Aoutlet = Binlet

Do you assume A and B have same oulet/inlet mesh/cell geeometry?

Read the manual for what sensor points are used.

Lee June 6, 2003 09:02

Re: How to do this?
Thanks again for your answer,sunlight007! I mean that I will compute one model,but the fully developed turbulent flow will be required at the inlet boundary,so I must create another model in order to get the fully developed inlet profile.that is all.

Anyway,thank you very much for your help and good advice!


Anton Lyaskin June 6, 2003 09:02

Re: How to do this?
You can set boundary conditions for A with table. To make a table: 1) run calculations for B, 2) loab boundary data from B-outlet (if it corresponds to A-inlet), 3) go to Graph->Load graph data... and load to graph registers boundary coordinates and data you've loaded before (you've loaded them into post rregisters, now you need them in graph registers), 4) go to Graph->Save graph data and save your graph registers into a text (i.e. 'coded') file, 5) read the manuals about table format (check Command Reference) and edit your file to make it look like a valid table. The last part can be the most difficult.

William June 9, 2003 10:08

Re: How to do this?
Use a pressure boundary instead of an inlet and switch your 'outlet' pressure boundary to a fixed flow-rate outlet boundary.

The profile at the 'inlet' pressure boundary will automatically be fully developed.

All times are GMT -4. The time now is 14:27.