CFX user defined value convergence

vitulaaak · August 7, 2014, 04:04

Hello,

in most of the cfd cases, I would like to evaluate the convergence based on the efficiency ( for turbines and compressors) as its usually the last parameter, that is settling.

In order to do so, I would like to use interruption criteria defined by an expression. And here is the catch. Would you happen to know, how to evaluate the values in expression vs. for example [nth] iteration?

e.g.:
delta_eta=eta[ last iteration] - eta [last iteration - 1]

This would really speed up my calculations.
Thank you for help
Vit

ghorrocks · August 7, 2014, 07:32

There is no easy way to do this with CEL.

It is pretty simple to do with user fortran if you want to go that way.

vitulaaak · August 7, 2014, 09:35

Hi,
i have never used fortran but that does not have to be a blocking point. If there is no ( easy or hard

) way directly in CFX, then I would use fortran.
Is it necessary to install any libraries? Is it free to use or paid?

Thank you
Vit

ghorrocks · August 7, 2014, 09:39

This is all described in the CFX (ANSYS) installation documentation.

vitulaaak · August 11, 2014, 04:32

Is there a way to do it without Fortran? I found, that it would be necessary to buy the compiler for ~900 usd.

ghorrocks · August 11, 2014, 07:47

Then install a Linux version of CFX and use a linux fortran compiler. You will not need to pay for anything then.

vitulaaak · August 14, 2014, 05:23

I am not sure, that this is an helpful answer. One could assume, that if you work in a company, that has some IT standards, you cannot install whatever you want and especially OS.

At the same time, its quite strange, that CFX requires paid software for compilation in Windows while it uses free compilers in Linux.

If there is no free version of compiler, what is the exact version of intel compiler that is required? At the same time, does it require anything else? Like visual studio?

Is there a way to compile the code not from CFX but from a windows command line?

Thank you

Lance · August 14, 2014, 05:51

I guess you can circumvent the fortran issue with some CEL.
Have you seen this post? (I havent tried it)
http://www.cfd-online.com/Forums/cfx...tml#post285482

ghorrocks · August 14, 2014, 07:36

My company supports both windows and linux. You can choose the most appropriate OS for your application. Maybe your IT department needs to catch up

It is not so strange - linux is an open source platform so you would expect many applications on it to also be open source.

Which compiler is required and how to do it is all discussed in the CFX documentation.

If fortran does not look appealing have a look Lance's suggestion.

August 7, 2014, 04:04	CFX user defined value convergence	#1
vitulaaak Member Vit Houst Join Date: Apr 2012 Posts: 35 Rep Power: 14	Hello, in most of the cfd cases, I would like to evaluate the convergence based on the efficiency ( for turbines and compressors) as its usually the last parameter, that is settling. In order to do so, I would like to use interruption criteria defined by an expression. And here is the catch. Would you happen to know, how to evaluate the values in expression vs. for example [nth] iteration? e.g.: delta_eta=eta[ last iteration] - eta [last iteration - 1] This would really speed up my calculations. Thank you for help Vit

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August 7, 2014, 07:32		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	There is no easy way to do this with CEL. It is pretty simple to do with user fortran if you want to go that way.

August 7, 2014, 09:35		#3
vitulaaak Member Vit Houst Join Date: Apr 2012 Posts: 35 Rep Power: 14	Hi, i have never used fortran but that does not have to be a blocking point. If there is no ( easy or hard ) way directly in CFX, then I would use fortran. Is it necessary to install any libraries? Is it free to use or paid? Thank you Vit

August 7, 2014, 09:39		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	This is all described in the CFX (ANSYS) installation documentation.

August 11, 2014, 04:32		#5
vitulaaak Member Vit Houst Join Date: Apr 2012 Posts: 35 Rep Power: 14	Is there a way to do it without Fortran? I found, that it would be necessary to buy the compiler for ~900 usd.

August 11, 2014, 07:47		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Then install a Linux version of CFX and use a linux fortran compiler. You will not need to pay for anything then.

August 14, 2014, 05:23		#7
vitulaaak Member Vit Houst Join Date: Apr 2012 Posts: 35 Rep Power: 14	I am not sure, that this is an helpful answer. One could assume, that if you work in a company, that has some IT standards, you cannot install whatever you want and especially OS. At the same time, its quite strange, that CFX requires paid software for compilation in Windows while it uses free compilers in Linux. If there is no free version of compiler, what is the exact version of intel compiler that is required? At the same time, does it require anything else? Like visual studio? Is there a way to compile the code not from CFX but from a windows command line? Thank you

August 14, 2014, 05:51		#8
Lance Senior Member Lance Join Date: Mar 2009 Posts: 669 Rep Power: 22	I guess you can circumvent the fortran issue with some CEL. Have you seen this post? (I havent tried it) http://www.cfd-online.com/Forums/cfx...tml#post285482

August 14, 2014, 07:36		#9
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	My company supports both windows and linux. You can choose the most appropriate OS for your application. Maybe your IT department needs to catch up It is not so strange - linux is an open source platform so you would expect many applications on it to also be open source. Which compiler is required and how to do it is all discussed in the CFX documentation. If fortran does not look appealing have a look Lance's suggestion.