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Old   December 21, 2011, 11:35
Default Automatically create Boundaries
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Hi,

i am currently trying to simulate the flow in a simple pipe with the floEFD Addin for Pro Engineer.
When i set the boundary conditions manually, it is no problem to run the simulation.

I read in a presentation, that it is possible to automatically extract the fluid volume, so that i only have to set the inlet and outlet conditions and the other surfaces are automatically defined as walls.

So i extracted the fluid volume of the pipe (a new part was created) and set up the simulations as i did before without creating a wall boundary.
When i start the simulation, the process stops during the mesh generation.
So i figured the problem has to be the missing wall-boundary.

Can someone tell me what to do to solve the problem?

Greetings
Philipp
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Old   January 16, 2012, 17:13
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Boris Marovic
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Hello,
If you are using FloEFD for Creo (former FloEFD for Pro/E or FloEFD.Pro) then I wonder why you need to set a wall boundary condition? Is there a special condition this wall needs such as heat source, fixed temperature, velocity or something like that?
In floEFD everything that is solid is solid and it's walls are automatically walls except if they are defined as inlet/outlet, disabled in the component controls or are defined as porous media and therfore as flow through volume or some sort of opening. This is standard, no need to tell that the wall is a wall as it is common in conventional CFD tools.

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Boris
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Old   January 16, 2012, 17:35
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Hi,

thanks for your reply.

The problem is that the walls are not generated by default.

I think the problem is my version of Pro Engineer. On another computer with a different version the boundaries were identified just fine.

Regards
Philipp
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Old   January 16, 2012, 17:55
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Boris Marovic
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Hi,
I think I don't quite understand what you mean with "walls". Do you mean a boundary condition of FloEFD or a geometrical feature on the CAD side?
Which version of Pro/E are you using?

Boris
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Old   January 17, 2012, 07:39
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Hi,

my problem was that the tool of FloEFD that automatically creates boundaries out of the CAD model did not work with my ProEngineer version.
By "walls" i meant the boundary conditions that are automatically created.

I am sorry but i cannot tell you the version I used because it was updated this year.

I also cannot use FloEFD any more because I only had a test license for a week to test the program.

Thanks for your help and replies
Regards
Philipp
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Old   January 17, 2012, 08:50
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Boris Marovic
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Ah ok, so you are not an experienced user. I just wondered because there is no tool in FloEFD that creates boundary conditions automatically. There is the wizard that you start to set up the basic conditions of your project such as selecting the fluid, if internal or external but all the boundary conditions such as heat sinks or flow inlets are not created automatically. Of course these are in some way boundary conditions the wizard applies but we usually speack of boundary condition when we talk about inlet openings or heat sources on a volume etc. so manually set boundary conditions.

I cannot really tell what the reason is why your calculation didn't work. Maybe there was something missing or the geometry was defect. This is hard to tell and one would need a look on your model and project you set up to find the issue.

Regards,
Boris
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Old   January 17, 2012, 10:16
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Hi,

I know there is a tool in FloEFD for ProEngineer that automatically creates a default wall boundary (as specified in the wizard) for all surfaces, so that all surfaces that are in contact with the fluid are treated as walls if they were not further specified (as inlet f.e.).
On another version of ProEngineer this worked fine.

Maybe I did not define the problem properly. My simulations worked but the problem was that I had to select each surface of the CAD model and define what kind of boundary condition should be applied there ( wall, inlet, outlet, ...). With another version of ProEngineer, I did not have to define the walls because the tool did this for me. The other boundaries such as inlets or outlet still had to be defined.

Regards
Philipp
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Old   January 17, 2012, 11:35
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Boris Marovic
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You really make me doubt myself. I worked with FloEFD products since 2007 and I don't know of any tool or need to define all walls that are not inlet or outlet as walls. I know that from other CFD tools but in FloEFD you don't need to do that. FloEFD automatically knows all solid walls are walls except you define otherwise as with a inlet condition. fOf course you can define additial wall roughness or ideal wall etc. to the walls but by default every wall is a "real wall" with 0 roughness (but not without friction).
I asked a colleague but he agrees, there is no need to define the walls as walls if they are not any different than the default.

Regards,
Boris
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Old   January 17, 2012, 12:48
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Hello Boris,

as you pointed out: normally floEFD sets all solids that border the fluid volume to walls.
(Therefore you need to define the fluid volume. That is the tool i meant)

My problem was that the walls were not set automatically. So i had to do this manually.

Regards
Philipp
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Old   January 17, 2012, 20:52
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Quote:
Originally Posted by Philipp Dietrich View Post
Hello Boris,

as you pointed out: normally floEFD sets all solids that border the fluid volume to walls.
(Therefore you need to define the fluid volume. That is the tool i meant)

My problem was that the walls were not set automatically. So i had to do this manually.

Regards
Philipp

Hi Philipp,,
I think you want to make fluid boundary..
I mean, you want to make lid.
Plane surface can make lid, no round surface..

Also, your model hae some problem, can't make lid..

Is that right your problem??
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Old   January 18, 2012, 07:33
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Hi,

I got no problems creating a lid.
As i said, the problem was that with my version of ProE it is apperently not possible to extract the boundaries of the fluid volume so that they are set by default to walls.
The creating of f.e. an inlet out of a lid surface was no problem.
But when i tried to start the simulation the program got stuck during the mesh generation due to a lack of boundaries.
When i created wall boundaries on the surfaces bordering the fluid volume the simulation worked fine.

I tested the exact same configuration on another computer with a different version of ProE, without manually setting the wall boundaries, and it worked fine.

Regards
Philipp
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Old   January 18, 2012, 08:35
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Boris Marovic
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Hi Philipp,
ok, I think the only solution would be to have a look on such a model because I never ever had to define any wall as "wall" except the properties for heat transfer (adiabat, heat transfer coefficient etc.) were different than the default. The fluid volume is automatically found (if watertight for internal, or any for external) and all solid objects in CAD are solid objects in FloEFD. Only if there are invalid contacts the fluid volume cannot be found but even then defining walls as walls would not help to solve this problem.
I really would need to see this model to say what the error is. It know that the accuracy settings in ProE to define gaps as gaps or contacts in the geometry definition can cause issues if they are set too large but this is saved in the model data and therefore the same model should not work on an other computer also except these settings are changed for the model but I think this has to be done in each part of the assembly too (not quite sure).

I worked 3 years in support for FloEFD and have never heard of anything like that so I believe there is something else wrong or we talk at cross-purposes.

Do you still have a working FloEFD version with that model?
I would be happy to do an online support session where I can switch onto your screen if that's ok.
I could contact you personally with my email etc.
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Old   January 18, 2012, 09:10
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Hi Boris,

thanks a lot for the offer.

As I said, I only had acces to floEFD for a week last year so now I have no acces to the cases and therefore no online support would be possible.

Simulation worked with exactly the same configuration on another computer with a different version of ProE but the same version of FloEFD. So the problem has to be the other version of ProE.

On my system, as I already mentioned, the simulation worked but I had to define each wall manually (The walls i defined in the wizard were not applied).
So I think the reason for the mesh generation getting stuck had to be the missing walls.

So all in all, I unfortunatelly cannot test any sugestions any more and either I am right concerning the different versions or I made a mistake setting up the simulation. (Tried different geometries, too, and got the same result.)

Thank you both for your help
Regards
Philipp
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Old   January 24, 2012, 22:46
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Quote:
Originally Posted by Philipp Dietrich View Post
Hi Boris,

thanks a lot for the offer.

As I said, I only had acces to floEFD for a week last year so now I have no acces to the cases and therefore no online support would be possible.

Simulation worked with exactly the same configuration on another computer with a different version of ProE but the same version of FloEFD. So the problem has to be the other version of ProE.

On my system, as I already mentioned, the simulation worked but I had to define each wall manually (The walls i defined in the wizard were not applied).
So I think the reason for the mesh generation getting stuck had to be the missing walls.

So all in all, I unfortunatelly cannot test any sugestions any more and either I am right concerning the different versions or I made a mistake setting up the simulation. (Tried different geometries, too, and got the same result.)

Thank you both for your help
Regards
Philipp

Hi..
Very interesting, I never heared about that..
I'll try soon, FloEFD pro.
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