FloEFD - Geometry Variations

sys999 · March 22, 2014, 07:00

Hi together,
I'm using FloEFD 12.1 and I'd like to simulate different geometry variations of one model consisting of many parts.

My attempt:
I import the geometry to EFD and supress some parts. Then I create a project (external, heat transfer) and start the simulation.
Now I'd like to unsupress a part, suppress another or add a new part to simulate it in a new project by cloning the old one.

The Problem:
When I'm trying to solve it, there occur many errors like invalid boundary conditions or thermal contact resistances. Many goals show a temperature of 0K.

I could create a new project and redefine all conditions/materials but that would mean a lot of work.

Why does that happen? Every boundary condition seems well defined.
What is the best procedure to simulate geometry variatons?

Boris_M · March 23, 2014, 10:01

Hi Sys999,

The reason is that if you change a component by deactivating it and activating a different one, the whole relation of goals as well as other boundary conditions (BC) are lost. The same would happen if you reference a new sketch for an extrusion to a surface of another component as you want the sketch to be located at that surface and reference the dimensions to the edges of that other component and then deactivate that component. All the references are linked to a component or face or edge that is not there anymore.

So if you deactivate a component that has some BCs and use a different one instead you will have to reapply the references to the new component. Simply edit the BCs and select the reference it has to have again and you are done.

Simulating Geometry variations of similar geometries where only dimensions have to be changed should be done by variants of that geometry which can be associated to that project. If the whole geometry is completely different then you have no other choice as to completely switch that and re-apply/-reference the BCs.

So just like in real life, if you move you will have to provide your friends with the new address otherwise they end up at at the wrong house. Whereas if you only move some furniture the address stays the same and it doesn't concern your friends :-)

I hope this helps,
Boris

sys999 · March 23, 2014, 11:02

Thanks so far...

"Simply edit the BCs and select the reference it has to have again and you are done."

The strange thing is that i dont't have extra BCs defined, as the simulation type is external.
The features I have applyed are:

- materials, assigned to every body
- volume heat sources
- a radiation surface
- a thermal contact resistance

All these features don't stay in contact with the component which I want to activate. That means the reference (faces and bodies) of the features don't change.

Boris_M · March 27, 2014, 20:27

If the old component doesn't have any boundary conditions applied to and you remeshed the model, then it should run without problems.
I noticed it might happen that a goal is reported invalid too but it is hard to tell what the reason is without a model.
I would suggest to send it to your support contact to have a look at it and see what might be the source.

Sorry I cannot help you any further,
Boris

March 22, 2014, 07:00	FloEFD - Geometry Variations	#1
sys999 New Member Bla Blubb Join Date: Dec 2010 Posts: 11 Rep Power: 15	Hi together, I'm using FloEFD 12.1 and I'd like to simulate different geometry variations of one model consisting of many parts. My attempt: I import the geometry to EFD and supress some parts. Then I create a project (external, heat transfer) and start the simulation. Now I'd like to unsupress a part, suppress another or add a new part to simulate it in a new project by cloning the old one. The Problem: When I'm trying to solve it, there occur many errors like invalid boundary conditions or thermal contact resistances. Many goals show a temperature of 0K. I could create a new project and redefine all conditions/materials but that would mean a lot of work. Why does that happen? Every boundary condition seems well defined. What is the best procedure to simulate geometry variatons?

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March 23, 2014, 10:01		#2
Boris_M Disabled Join Date: Jul 2009 Posts: 616 Rep Power: 23	Hi Sys999, The reason is that if you change a component by deactivating it and activating a different one, the whole relation of goals as well as other boundary conditions (BC) are lost. The same would happen if you reference a new sketch for an extrusion to a surface of another component as you want the sketch to be located at that surface and reference the dimensions to the edges of that other component and then deactivate that component. All the references are linked to a component or face or edge that is not there anymore. So if you deactivate a component that has some BCs and use a different one instead you will have to reapply the references to the new component. Simply edit the BCs and select the reference it has to have again and you are done. Simulating Geometry variations of similar geometries where only dimensions have to be changed should be done by variants of that geometry which can be associated to that project. If the whole geometry is completely different then you have no other choice as to completely switch that and re-apply/-reference the BCs. So just like in real life, if you move you will have to provide your friends with the new address otherwise they end up at at the wrong house. Whereas if you only move some furniture the address stays the same and it doesn't concern your friends :-) I hope this helps, Boris

March 23, 2014, 11:02		#3
sys999 New Member Bla Blubb Join Date: Dec 2010 Posts: 11 Rep Power: 15	Thanks so far... "Simply edit the BCs and select the reference it has to have again and you are done." The strange thing is that i dont't have extra BCs defined, as the simulation type is external. The features I have applyed are: - materials, assigned to every body - volume heat sources - a radiation surface - a thermal contact resistance All these features don't stay in contact with the component which I want to activate. That means the reference (faces and bodies) of the features don't change.

March 27, 2014, 20:27		#4
Boris_M Disabled Join Date: Jul 2009 Posts: 616 Rep Power: 23	If the old component doesn't have any boundary conditions applied to and you remeshed the model, then it should run without problems. I noticed it might happen that a goal is reported invalid too but it is hard to tell what the reason is without a model. I would suggest to send it to your support contact to have a look at it and see what might be the source. Sorry I cannot help you any further, Boris