[Mina_Shahi]

Dear Cfx users

I modeling two way fluid structure interaction in Workbench. my simulation was crashed i have .db file and also .rdb file from structural part and i also have .res file from fluid part. now my question is how to use them .

because when you use wb initialization can be either initial condition or current simulation so my question is how to select the . res file from last restarting point.

and when i select rdb file or db file in multifield tab, i have this error :

update of the solution component in copy of fluid flow failed. Expected 1 solver task sand box but two were found

Can anybody help me please?

1.jpj.jpg

[sajad_abasi]

how do you model your problem?
one way or two way?

[Mina_Shahi]

Yes i am simulation 2 way interaction.

[sajad_abasi]

i saw the pic that you attached.it seems that you conect so many objects.for simulating a fsi problem in 2-way you need to have static structural ansys and cfx.then conect there geometry and then conect static structural setup to cfx setup.
are you modelling your simulation in this way?

[stumpy]

I'm not too sure how you have a .res file, since if it crashed the CFX solver generally wouldn't have written one. If you want to restart from a backup point you need to make sure you create regular backup points. In CFX this is done under Output Control. In Mechanical you need to use a Command Snippet and insert the MFRC command. If you also use the MFOU command you need to make sure data is written to the rst file at the time points set by MFRC. For example:
MFOU,10
MFRC,100,1
would be OK, since at the 100th timestep data would be written to the rst file and a restart point would be created by MFRC.

[Mina_Shahi]

Yes i set "MFROU 10 " and "MFRC,5,1" so i have restarting file.
but the problem is perhaps related to running on the background. i am running on cluster so i switch run in background, with this case i don't need to leave my lap top on always.
i just understood that if it crashed or if you stop it when it is running on background you should select the reconnect botton on the top of screen.
and after that i am able to use the restarting point.

[Mina_Shahi]

Thanks Stumpy

I have another question, as I told I am running my case on cluster. So I am doing that
Just by clicking on solution cell>select switch active solution to background
So after that the save botton will be active and also you are able to open or edit set up cells or …
After saving and quitting the solver run will still continue.
That what I was doing, but now my problem is that whenever I switch with active solution to background and then save it and quit it, it stop running which is weird.
Can anyone please help me with this matter? This is really a big deal because I am using a lap top and I can’t always keep it on or… , so I have to switch it on background which means it keep running on cluster .

[Mina_Shahi]

Originally Posted by sajad_abasi

i saw the pic that you attached.it seems that you conect so many objects.for simulating a fsi problem in 2-way you need to have static structural ansys and cfx.then conect there geometry and then conect static structural setup to cfx setup.
are you modelling your simulation in this way?

Yes sajad, i am doing in this way.

[Mina_Shahi]

Originally Posted by stumpy

I'm not too sure how you have a .res file, since if it crashed the CFX solver generally wouldn't have written one. If you want to restart from a backup point you need to make sure you create regular backup points. In CFX this is done under Output Control. In Mechanical you need to use a Command Snippet and insert the MFRC command. If you also use the MFOU command you need to make sure data is written to the rst file at the time points set by MFRC. For example:
MFOU,10
MFRC,100,1
would be OK, since at the 100th timestep data would be written to the rst file and a restart point would be created by MFRC.

Thanks Stumpy

I have another question, as I told I am running my case on cluster. So I am doing that
Just by clicking on solution cell>select switch active solution to background
So after that the save botton will be active and also you are able to open or edit set up cells or …
After saving and quitting the solver run will still continue.
That what I was doing, but now my problem is that whenever I switch with active solution to background and then save it and quit it, it stop running which is weird.
Can anyone please help me with this matter? This is really a big deal because I am using a lap top and I can’t always keep it on or… , so I have to switch it on background which means it keep running on cluster .

[stumpy]

I've never tried to leave it running in the background and switch off my machine. Are you allowed to do that? I'm not surprised the simulation stops, but if it's supposed to work then I would ask ANSYS support.

[Mina_Shahi]

Originally Posted by stumpy

I've never tried to leave it running in the background and switch off my machine. Are you allowed to do that? I'm not surprised the simulation stops, but if it's supposed to work then I would ask ANSYS support.

Yes we are allowed to do that. i was always running on background. but i don't know why i have this problem now.
when you use cluster and you are modeling a big geometry which takes long time you can't always keep lap top or pc online , some times you may have network connection error or .... so you can keep it running on the cluster and turn off your pc safely.
I will be thankful if you could make it.

[Mina_Shahi]

Originally Posted by stumpy

I'm not too sure how you have a .res file, since if it crashed the CFX solver generally wouldn't have written one. If you want to restart from a backup point you need to make sure you create regular backup points. In CFX this is done under Output Control. In Mechanical you need to use a Command Snippet and insert the MFRC command. If you also use the MFOU command you need to make sure data is written to the rst file at the time points set by MFRC. For example:
MFOU,10
MFRC,100,1
would be OK, since at the 100th timestep data would be written to the rst file and a restart point would be created by MFRC.

i want to use a back up file for restarting from a fail run.

i have these for ansys part :

MFOU,10
MFRC,50,1

and i also set the same back up for CFX.

but now the problem is that i don't know how to use them? i mean in defining run in multifield tab i used the .db file. i don't know if i should look for another mechanical input file? and also i don't know how to use .back file from cfx.

can you please help me with that??