# Custom Field Functions: Data from different locations

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 May 22, 2016, 23:21 Custom Field Functions: Data from different locations #1 New Member   Chris Join Date: May 2016 Posts: 10 Rep Power: 3 Sponsored Links Hello, I'm a greenhorn in CFD and so my question regarding Custom Field Functions may be really basic: I simulate a flow around a blade of a turbomachine. Now I would like to calculate the loss coefficient zeta at a measurement line 50 mm behind the blade with zeta = delta(ptot)/((rho/2)/c1^2). I tried to do this with a custom field function, but for the calculation I need data from two different locations: The total pressure and the velocity from the inlet and the total pressure at the measurement line. So far I entered the data from the inlet manually. But is there a way so integrate these data automatically? Thanks for your help! Greetings Chris

 May 23, 2016, 15:04 #2 Member   nm Join Date: Mar 2013 Posts: 79 Rep Power: 6 As far as I know, CFFs are field functions, ie. they are general functions for the entire domain and has a value at every point. You cannot take input values from a particular boundary for a CFF. CFF is a "function". You might want to look into macros. Or better, if you have CFX you can use the expressions there to calculate this accurately.

 May 24, 2016, 20:12 #3 Senior Member   Lucky Tran Join Date: Apr 2011 Location: Orlando, FL USA Posts: 1,854 Rep Power: 26 Custom field functions are field functions. What you are trying to do is a simple expression. It's awkward to do this in Fluent, much easier to do in CFD post, excel, matlab, by hand, etc. Although, you can do the integration in Fluent using surface monitors. But to evaluate the complete expression is a little weird. You can do it with Fluent scheme commands, but what is the point? What would you do with the resulting value? Is automation in Fluent really needed?

 May 25, 2016, 06:28 #4 New Member   Chris Join Date: May 2016 Posts: 10 Rep Power: 3 Thanks! I'll use matlab for this – this is the most comfortable way for me. I can export the data files I need (total pressure, velocity etc.) and write a script in Matlab.

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post atheresia ANSYS 0 February 16, 2014 13:03 haakon OpenFOAM Programming & Development 3 September 25, 2012 10:01 matteo_gautero OpenFOAM Running, Solving & CFD 0 February 28, 2008 07:51 sivakumar FLUENT 1 October 12, 2001 06:36 ak FLUENT 2 October 8, 2001 10:23