CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent UDF and Scheme Programming

UDF boundary condition (heat flux), in corrugated area (adjustment factor needed))

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   June 10, 2021, 00:57
Default UDF boundary condition (heat flux), in corrugated area (adjustment factor needed))
New Member
Jose Martin
Join Date: Jan 2021
Posts: 6
Rep Power: 2
JMM_UC3M is on a distinguished road
Hi all,

First of all I would like to thank you for having a look my problem and helping me to solve it!

I have prepared a small document to describe my problem (please find the attached file), and I would like you to help me with the UDF definition, because the solution I have found does not work (there is a small deviation, you can see it in the last pic of the attached file).

Here the description, and all details in the attached file:

"I need to extrapolate the projected received heat flux for a corrugated area. Thus, I need to include in the UDF a factor in order to take it into account. The problem is for a corrugated tube, which receives a constant value of radiative heat flux, and if I corrugate the tube, the flux in this specific area will be lower (because the face cell projected area devided by the face cell area is smaller than 1, and this factor is what I need to include in the UDF), then to extrapolate this dimensional factor I would like to define a factor which is the projected area in Z coordinate (where the heat flux is constant) devided by the face area"

The UDF definition (just for theis factor) is a follow :

F_AREA(A,f,t); /* Function projected area */

AA=pow(A[0]*A[0]+A[1]*A[1],0.5)/NV_MAG(A); /* Factor to adjust the received heat flux in the face cell*/

QMAX=AA*Q; /* Adjusted heat flux*/

Hope you can help me, I guess it is not a very complicated issue, but I do not find the solution.

Many thanks in advance

Solution: When defining variables it needs to be "double" instead of "real", even I am runing the simulations in double precision..... I thought it was a tolerance problem....

Last edited by JMM_UC3M; June 10, 2021 at 07:08.
JMM_UC3M is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Radiation in semi-transparent media with surface-to-surface model? mpeppels CFX 11 August 22, 2019 07:30
Error - Solar absorber - Solar Thermal Radiation MichaelK CFX 12 September 1, 2016 05:15
Basic Nozzle-Expander Design karmavatar CFX 20 March 20, 2016 08:44
Radiation interface hinca CFX 15 January 26, 2014 17:11
Enforce bounds error with heat loss boundary condition at solid walls Chander CFX 2 May 1, 2012 20:11

All times are GMT -4. The time now is 13:00.