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-   -   Transient boundary conditions (http://www.cfd-online.com/Forums/fluent/34293-transient-boundary-conditions.html)

Dave July 29, 2004 11:56

Transient boundary conditions
 
Basically my geometry consists of a pressure inlet and 4 pressure outlets (representing the air intake system with intake ports on a four cylinder engine), but only 1 of the outlets is open at once, when that one closes, another opens. How do I model this in FLUENT, do I need a UDF and how would I go about writing a UDF to do this? Bear in mind that my programming skills are virtually nil! Any help would be greatly appreciated!!!

Thanks Dave

Gica August 2, 2004 07:55

Re: Transient boundary conditions
 
I'm having the same problem, but with a pressure inlet, and 2 pressure outlets. I have no idea how to get on with it.

Gica August 3, 2004 05:08

Re: Transient boundary conditions
 
How do I simulate an inlet/outlet port? I mean in one part of the process, it pushes the fluid inside, and in another part, it is pushed outwards by the fluid?

Ravi August 7, 2004 08:06

Re: Transient boundary conditions
 
hello,

Even i have the same problem, but in my case there is a piston which inside a cylinder. When it moves to one end of the cylinder it closes an opening and dwells there for 2 minutes and comes back and closes an opening at the end and moves back again. in this manner it oscillates to and fro.

And this movement of the piston is caused by increase in pressure on one side while decrease on other side. I think this is totally a fluid structure interaction problem.

Can you help me in writing a UDF for this.

thanks RAvi

Ravi August 7, 2004 08:41

Re: Transient boundary conditions
 
hello,

Even i have the same problem, but in my case there is a piston which is inside a cylinder. When it moves to one end of the cylinder it closes an opening and dwells there for 2 minutes and comes back and closes an opening at the other end and moves back again. in this manner it oscillates to and fro.

And this movement of the piston is caused by increase in pressure on one side while decrease on other side. I think this is totally a fluid structure interaction problem.

Can you help me in writing a UDF for this.

thanks Ravi


idrul October 30, 2011 09:58

in cylinder engine problem
 
hi i'm having a problem on in cylinder simulation..does anybody know how to define boundary condition for in cylinder engine mesh by using gambit software..and plz help me on how to do moving mesh as well..:)


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