Pessure BC case

Studentdrak · March 31, 2012, 02:18

Hello everyone,

I have tried running my case with a pressure inlet BC, but it has just not even done the first iteration for past 15hrs.

The same case runs fine with velocity specified inlet.

I understand that pressure inlet is computationally complex.

But what should i do to make my case run with a pressure inlet?

Kindly reply asap.

Thanks

Studentdrak · March 31, 2012, 04:03

My simulation exited after 6 iterations. Saying "Floating point exception: overflow

any suggestions?

ghorrocks · March 31, 2012, 07:18

Search the forum. Floating point error has been discussed zillions of times.

Far · April 1, 2012, 10:42

Could you describe your problem with some details. If possible please post some pics

Studentdrak · April 1, 2012, 10:46

Mine is a little complex internal flow system.

I tried the case with reduced relative total pressure at inlet, and the case is running.

any suggestions pl.?

ghorrocks · April 4, 2012, 07:24

As I said, this question has been asked a million times. I really shoudl write an FAQ on it one day.

Your simulation is numerically unstable. You need to improve the stability - improve mesh quality and smaller time steps (at least to start with) are the general approach to address it.

Studentdrak · April 5, 2012, 10:18

will try reducing the time step n improving mesh

March 31, 2012, 02:18	Pessure BC case	#1
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 14	Hello everyone, I have tried running my case with a pressure inlet BC, but it has just not even done the first iteration for past 15hrs. The same case runs fine with velocity specified inlet. I understand that pressure inlet is computationally complex. But what should i do to make my case run with a pressure inlet? Kindly reply asap. Thanks

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March 31, 2012, 04:03		#2
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 14	My simulation exited after 6 iterations. Saying "Floating point exception: overflow any suggestions?

March 31, 2012, 07:18		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Search the forum. Floating point error has been discussed zillions of times.

April 1, 2012, 10:42		#4
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	Could you describe your problem with some details. If possible please post some pics

April 1, 2012, 10:46		#5
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 14	Mine is a little complex internal flow system. I tried the case with reduced relative total pressure at inlet, and the case is running. any suggestions pl.?

April 4, 2012, 07:24		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	As I said, this question has been asked a million times. I really shoudl write an FAQ on it one day. Your simulation is numerically unstable. You need to improve the stability - improve mesh quality and smaller time steps (at least to start with) are the general approach to address it.

April 5, 2012, 10:18		#7
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 14	will try reducing the time step n improving mesh