Hi,

I am going to simulate unsteady flow in an intake manifold. I have one inlet and 4 outlet. I have all pressures in inlet and outlet boundaries in all times. But sometimes outlets should be closed. So I have to change outlet boundary condition to wall condition and then change it to pressure outlet again. I think, I need to use a UDF.

Is it right?

How can I do that?

I am beginner in this subject.

BEst Regards, David

I think instead of using a udf U can try this with Exceute commands. Since the applying condition is periodic, u can excute the macro to change the boundary condition with that periodicity. I think this may help u.

Could you tell me more?

I don't understand.

BR, David

Hi, In execute commands, we can execute macros(see for help in execute commands). We can perform certain repeated tasks for every specified number of iterations or time steps. For example we can write files for every 10 time steps for phase averaging and so on. May be u can write a macro for changing the boundary condition after specified number of time steps from pr outlet to wall and change back again. But I have a doubt whether one can change B.C while solving. Well we try that out. Hope this works.. Tell me when it works.

[Sergiu]

Originally Posted by ramesh
;121117

Hi, In execute commands, we can execute macros(see for help in execute commands). We can perform certain repeated tasks for every specified number of iterations or time steps. For example we can write files for every 10 time steps for phase averaging and so on. May be u can write a macro for changing the boundary condition after specified number of time steps from pr outlet to wall and change back again. But I have a doubt whether one can change B.C while solving. Well we try that out. Hope this works.. Tell me when it works.

Hi Ramesh and David,

I'm trying the allmost the same simulation like david and also I don't now how to use that execute comand in order to open each valve!

David: did you find how to do this with execute comand?
Ramesh: Could you help me doing this?