Opening like boundary condition

Questions and remarks about code_saturne usage
Forum rules
Please read the forum usage recommendations before posting.
ruedavallejo
Posts: 5
Joined: Mon Aug 26, 2013 5:30 pm

Opening like boundary condition

Post by ruedavallejo »

Hi group,

I'm simulating buoyancy in an enclosure with lateral openings. Air can exit or enter the enclosure depending on the conditions and flow it's not necessarily normal to the boundary. What could be the best way to implement an opening like boundary condition?

Thanks and kind regards,

Néstor,
Brian Angel
Posts: 98
Joined: Mon Jul 22, 2013 12:53 pm

Re: Opening like boundary condition

Post by Brian Angel »

Hello,

In version 4.0 there is a boundary condition available (in the GUI) called Free Inlet/Outlet which should provide what you are looking for.

Regards,

Brian Angel.
ruedavallejo
Posts: 5
Joined: Mon Aug 26, 2013 5:30 pm

Re: Opening like boundary condition

Post by ruedavallejo »

Thanks Brian,

I downloaded CS 4.0 beta and it's there, however I haven't been able to make my example model run with a free condition (got a SIGSEGV error). I have only used numeric values for the external head losses definition. Do you have by any chance a reference for the definition of this BC?

Regards,

Néstor.
Brian Angel
Posts: 98
Joined: Mon Jul 22, 2013 12:53 pm

Re: Opening like boundary condition

Post by Brian Angel »

Hello Néstor,

Unfortunately I do not have any examples. Can you upload your case so that I can take a look?

Regards,

Brian Angel.
ruedavallejo
Posts: 5
Joined: Mon Aug 26, 2013 5:30 pm

Re: Opening like boundary condition

Post by ruedavallejo »

Hi Brian, please find the link to my example model (file is 2.3 Mb but limit here is 2 Mb, I hope this is not a problem).

It’s a kind of “tee”, one inlet, one outlet and one free BC. It’s a very rough model since I was trying to obtain a result and also trying to “stress test” the application and the condition. The same model runs ok with no free BC (either using an inlet or an outlet). I’m using Ubuntu 14.04 LTS. BTW, I haven’t been able to install MED but that’s another story.

Thanks again and have a nice day,

Néstor

https://www.dropbox.com/s/l0xm1jv2v6wu7 ... ar.gz?dl=0
vgm567
Posts: 17
Joined: Tue Oct 14, 2014 3:51 pm

Re: Opening like boundary condition

Post by vgm567 »

Brian Angel wrote:Hello,

In version 4.0 there is a boundary condition available (in the GUI) called Free Inlet/Outlet which should provide what you are looking for.

Regards,

Brian Angel.
Hello,

Please could you provide further info on this BC. Especially how to implement using subroutine and also if possible to implement this in earlier version 3.2.x.

Thanks
Brian Angel
Posts: 98
Joined: Mon Jul 22, 2013 12:53 pm

Re: Opening like boundary condition

Post by Brian Angel »

Hello,

Below is an example of coding using a free inlet-outlet boundary types condition for two different boundaries. This coding has worked for us on another case where a pressure is used to drive the flow.

call getfbr('outlet', nlelt, lstelt)
!==========
do ilelt = 1, nlelt
ifac = lstelt(ilelt)
itypfb(ifac) = isolib
icodcl(ifac,ipr) = 1
rcodcl(ifac,ipr,1) = P0
icodcl(ifac,iu) = 3
icodcl(ifac,iv) = 3
icodcl(ifac,iw) = 3
rcodcl(ifac,iu,3) = 0
rcodcl(ifac,iv,3) = 0
rcodcl(ifac,iw,3) = 0
enddo

call getfbr('inlet', nlelt, lstelt)
!==========
do ilelt = 1, nlelt
ifac = lstelt(ilelt)
itypfb(ifac) = ifrent
icodcl(ifac,ipr) = 1
rcodcl(ifac,ipr,1) = P0+dp
icodcl(ifac,iu) = 3
icodcl(ifac,iv) = 3
icodcl(ifac,iw) = 3
rcodcl(ifac,iu,3) = 0
rcodcl(ifac,iv,3) = 0
rcodcl(ifac,iw,3) = 0
enddo

Best regards,

Brian Angel.
vgm567
Posts: 17
Joined: Tue Oct 14, 2014 3:51 pm

Re: Opening like boundary condition

Post by vgm567 »

Hi ,

I hope you can help me further with the new Free inlet/outlet BC in v4.0.1 I can see this selection in GUI and I read the explanation about the pressure BC in Section 5.4.5 of Theory guide. I am using a build without XML support so I would like to implement this BC on my outlet faces through cs_user_boundary_conditions.f90.

It is my understanding that choosing just standard 'isolib' type for the outlet imposes a free outlet (icodcl=9) BC on the velocity. In this new BC type how is the treatment for velocity different? Does it allow both incoming/outgoing flow at the selected face ?

Many thanks

V. Michael
Brian Angel
Posts: 98
Joined: Mon Jul 22, 2013 12:53 pm

Re: Opening like boundary condition

Post by Brian Angel »

Hello,

I'll have a look and come back to you.

Regards,

Brian Angel.
vgm567
Posts: 17
Joined: Tue Oct 14, 2014 3:51 pm

Re: Opening like boundary condition

Post by vgm567 »

Thanks. Hope to get some information on this BC and how to setup in cs_user_boundary_conditions.f90 Just for the record, I am unable to get this BC working using GUI either. I receive a crash at first time-step with
"SIGSEGV signal (forbidden memory area access) intercepted!"

Regards

V Michael
Brian Angel wrote:Hello,

I'll have a look and come back to you.

Regards,

Brian Angel.
Post Reply