setting up multiple models in CFX

NGlo · December 9, 2010, 08:39

Hi all

I'm new to CFX and have a question I hope someone can help me with.

I'd like to set up and solve 100 versions of the same base model only changing the values of 5 of the input parameters for each run.
I don't want to do this manually (i.e. setting up 100 .def files). I know ccl files can be used to easily adapt .def files but would this require me to create 100 ccl files, one for each run? I realise this wouldn't take too long but as it's something I will be doing on a regular basis I'd like to know if there is a simpler way of doing this.

Has anyone had experience of this? Any advice would be greatly appreciated.

Thank you in advance.

siw · December 9, 2010, 09:59

Would the Parameter/Design Point feature in Workbench be able to change your inputs without having to make lots of files?

I think it depends what you want to change: numerical input values (velocity, temperature etc) it should be okay but it wont change CFX settings (as far as I can see). If so you'd have to run CFX in Workbench rather than standalone. I've not tried this myself, only taken a quick look through the Workbench User's Guide.

joey2007 · December 9, 2010, 15:08

siw is right. It can be done with workbench quite simple and without GUI. Just start CFX-Pre with wb and setup your case. If you like to do it for an inlet temperature for example, just set a CEL expression. You can choose an arbitrary name for the CEL expression. Assuming you have chosen Tinlet. Then goto the boundary condition and use Tinlet there for temperature. Go back to expressions and right click on Tinlet. You will get the option set Input parameter. If you use the option, wb will generate a parameter table on the project page. There you can duplicate design points and control the simulations. Before varying your parameters you have to define an output parameter in CFX post in a similar manner. Once you have learned the procedure, it is quite convient. You can parametrizen anything which is controlable by CEL. IMHO this feature is really a strength of ANSYS.

From the CFX pre-ANSYS times there is also some PERL interface remaining. It can also be used to script such things. Guess the service can provide you some example scripts.

singer1812 · December 9, 2010, 16:53

If you run outside of WB you can do this with CEL. If your job is SS, set up expression based on step and citern or aitern. Check those out in the docs.

NGlo · December 14, 2010, 08:49

Thanks for all the advice. I tried both the work bench method using the design points and writing a script. Both methods worked very well and will save me alot of time in the future.

Thanks again.

December 9, 2010, 08:39	setting up multiple models in CFX	#1
NGlo New Member Join Date: Dec 2010 Posts: 2 Rep Power: 0	Hi all I'm new to CFX and have a question I hope someone can help me with. I'd like to set up and solve 100 versions of the same base model only changing the values of 5 of the input parameters for each run. I don't want to do this manually (i.e. setting up 100 .def files). I know ccl files can be used to easily adapt .def files but would this require me to create 100 ccl files, one for each run? I realise this wouldn't take too long but as it's something I will be doing on a regular basis I'd like to know if there is a simpler way of doing this. Has anyone had experience of this? Any advice would be greatly appreciated. Thank you in advance.

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December 9, 2010, 09:59		#2
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 733 Rep Power: 25	Would the Parameter/Design Point feature in Workbench be able to change your inputs without having to make lots of files? I think it depends what you want to change: numerical input values (velocity, temperature etc) it should be okay but it wont change CFX settings (as far as I can see). If so you'd have to run CFX in Workbench rather than standalone. I've not tried this myself, only taken a quick look through the Workbench User's Guide.

December 9, 2010, 15:08		#3
joey2007 Senior Member Join Date: Mar 2009 Location: Europe Posts: 169 Rep Power: 17	siw is right. It can be done with workbench quite simple and without GUI. Just start CFX-Pre with wb and setup your case. If you like to do it for an inlet temperature for example, just set a CEL expression. You can choose an arbitrary name for the CEL expression. Assuming you have chosen Tinlet. Then goto the boundary condition and use Tinlet there for temperature. Go back to expressions and right click on Tinlet. You will get the option set Input parameter. If you use the option, wb will generate a parameter table on the project page. There you can duplicate design points and control the simulations. Before varying your parameters you have to define an output parameter in CFX post in a similar manner. Once you have learned the procedure, it is quite convient. You can parametrizen anything which is controlable by CEL. IMHO this feature is really a strength of ANSYS. From the CFX pre-ANSYS times there is also some PERL interface remaining. It can also be used to script such things. Guess the service can provide you some example scripts.

December 9, 2010, 16:53		#4
singer1812 Senior Member Edmund Singer P.E. Join Date: Aug 2010 Location: Minneapolis, MN Posts: 511 Rep Power: 20	If you run outside of WB you can do this with CEL. If your job is SS, set up expression based on step and citern or aitern. Check those out in the docs.

December 14, 2010, 08:49		#5
NGlo New Member Join Date: Dec 2010 Posts: 2 Rep Power: 0	Thanks for all the advice. I tried both the work bench method using the design points and writing a script. Both methods worked very well and will save me alot of time in the future. Thanks again.