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#1 |
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Hi all, I have following problem. The geometry is very simple: air enters the pipe from one side under pressure. On the other side there is valve: the valve could be in one of two positions: "closed" where no flow is possible (pipe closed from one side) and "opened" where sucking occurs through the valve. The valve opens and closes periodicaly. I am using UDF to represent changes of the valve state in time but I dont know how to simulated closed valve with pressure BC.
Any ideas? Luk |
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#2 |
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Why donīt you change your pressure outlet to wall and backwards ?
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#3 |
Guest
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Is it possible with UDF? I mean is it possible to periodicaly change type of BC for specified surface/face?
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#4 |
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I didnīt work much with UDFīs. But Iīm sure you can handle that with a journal file. The question is how often do you open and close?
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#5 |
Guest
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About 100/sec. The size of the pipe is few cm in diameter and about 50cm length. Pressures are rather low.
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#6 |
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O.K., i tried some things. To change the boundary condition with a journal file is possible. To start the journal file with an execute-comand works too. So there is a posibility to automate the whole thing but itīs a long way.
Maybe someone else knows an alternative. |
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#7 |
Guest
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Dear Sir, Thanks for Your kind help! I'll try this solution today in few hours.
Luk |
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#8 |
Guest
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last chance for me to help you is tomorrow, then Iīm on holiday for 2 weeks - Jippie!!!!
The execute comand to start the journal is easy : file read-journal nameofjournal the journal comands to switch from wall to pressure outlet : define boundary-condition modify-zones zone-type ( ID number of your face you want to switch ) pressure-outlet ( or wall when you switch back ) but be careful the settings of your pressure outlet are set to the default values. you can change them with : define boundary-condition pressure-outlet good luck |
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#9 |
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I wish Your nice holydays! Could You be so kind and send me email for further contact: my address is Lukasz.Czopyk@ifj.edu.pl. I promise not to disturb Your free time anyway.
![]() Luk |
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