# udf eror + Define property + density

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

 August 29, 2011, 08:54 udf eror + Define property + density #1 New Member   rezvan Join Date: Aug 2011 Location: Mashhad,iran Posts: 10 Rep Power: 5 hi,I want to assign a high density (infinity) to a region of my 2D model. I have writen the following code; #include "udf.h" DEFINE_PROPERTY(cell_density, cell, thread) { real density; real grid_y = NODE_Y(cell, threads); real grid_x = NODE_X(cell, threads); if ( grid_x >= 30. && grid_x <= 40. ) { if ( grid_y >= 10. && grid_y <= 20. ) { density =1000000000; } } } but I have received the following error: line 5: macro `NODE_Y' used with too many (2) args can anyone help me with it?

 August 29, 2011, 09:24 #2 Member     Join Date: Apr 2009 Posts: 46 Rep Power: 8 See the definition: Code: `#define NODE_Y(v) (NODE_COORD(v)[1])`

 August 29, 2011, 09:36 #3 Senior Member     Amir Join Date: May 2009 Location: Shiraz, Iran Posts: 739 Blog Entries: 1 Rep Power: 14 Hi, you wouldn't need any UDF for this case; separate desired space and set different density. __________________ Amir

 August 29, 2011, 10:29 re #4 New Member   rezvan Join Date: Aug 2011 Location: Mashhad,iran Posts: 10 Rep Power: 5 hi,thanks for ur replying,you say true,but my teacher tell me that i should solve this problem with udf,please say me what i should to do?please write all of the udf(i am in the start of the writing udf)thanks

August 29, 2011, 10:45
#5
Senior Member

Amir
Join Date: May 2009
Location: Shiraz, Iran
Posts: 739
Blog Entries: 1
Rep Power: 14
Quote:
 Originally Posted by rezvan hi,thanks for ur replying,you say true,but my teacher tell me that i should solve this problem with udf,please say me what i should to do?please write all of the udf(i am in the start of the writing udf)thanks
Dear Rezvan,
for such cases, we use cell values instead of node ones. I didn't check this UDF; check 2 rho vales:
Code:
```#include "udf.h"
DEFINE_PROPERTY(my_density, c, t)
{
real rho;
real cr[ND_ND];
C_CENTROID(cr,c,t);
if ( cr[0] >= 30. && cr[0] <= 40. && cr[1] >= 10. && cr[1] <= 20.)
{
rho =1000000000;
}
else
{
rho=1.0; //check that
}
return rho;
}```
Bests,
__________________
Amir

 August 29, 2011, 20:56 rep #6 New Member   rezvan Join Date: Aug 2011 Location: Mashhad,iran Posts: 10 Rep Power: 5 hi,i am really thank you,i take a lot of ur time,exuse me,when i interpreted this udf,acure this eror: line 1: parse error. plz help me

 August 29, 2011, 20:58 #7 New Member   rezvan Join Date: Aug 2011 Location: Mashhad,iran Posts: 10 Rep Power: 5 dear fox000002 ,hi,thank u a lot,i am in the start of writting udf,plz SITUATION your sentence in my udf

August 30, 2011, 04:45
#8
Senior Member

Amir
Join Date: May 2009
Location: Shiraz, Iran
Posts: 739
Blog Entries: 1
Rep Power: 14
Quote:
 Originally Posted by rezvan hi,i am really thank you,i take a lot of ur time,exuse me,when i interpreted this udf,acure this eror: line 1: parse error. plz help me
Hi,
I checked that both as interpreted and compiled one and there is not any error!
maybe there is a problem in your text editor. use this attached file.

Bests,
Attached Files
 density.c (232 Bytes, 50 views)
__________________
Amir

 August 30, 2011, 06:43 s #9 New Member   rezvan Join Date: Aug 2011 Location: Mashhad,iran Posts: 10 Rep Power: 5 hi,thank u a lot...with ur help,my problem solved,bud if u have time ,i am glading that u answer to my other guestions : 1=this program must be .h or .c ? 2=in this udf whats the meaning and aplication of these words: ("real" and "rho" and "cr[ND_ND] and "C_CENTROID(cr,c,t)" 3=and my importand guestion is that : why u answer to my guestions and other guestion of every peaple ?and spend alot of ur time for me & others? Last edited by rezvan; August 30, 2011 at 07:21.

August 30, 2011, 08:12
#10
Senior Member

Amir
Join Date: May 2009
Location: Shiraz, Iran
Posts: 739
Blog Entries: 1
Rep Power: 14
Quote:
 Originally Posted by rezvan hi,thank u a lot...with ur help,my problem solved,bud if u have time ,i am glading that u answer to my other guestions : 1=this program must be .h or .c ?
this is a main program part which includes execution macro and should be stored in .C extension; .H extension are header files which are generally consist of class definitions such as udf.h. for more info, it's better to refer to C or C++ documentations.
Quote:
 Originally Posted by rezvan 2=in this udf whats the meaning and aplication of these words: ("real" and "rho" and "cr[ND_ND] and "C_CENTROID(cr,c,t)"
real-> type definition(float); it's a class
rho-> just a name; it's an object in real class
cr[ND_ND]-> self adjusting dimension array in 2D or 3D solvers; i.e., in 2D it's cr[2] and in 3D it's cr[3]
C_CENTROID(cr,c,t)-> it stores center cell coordinate of cell index c which belongs to thread t in array cr
Quote:
 Originally Posted by rezvan 3=and my importand guestion is that : why u answer to my guestions and other guestion of every peaple ?and spend alot of ur time for me & others?
I'll be glad if I can help others; in this forum, you can improve your CFD knowledge regardless that you ask a question or answer that. Many questions don't take much time; like yours.

Bests,
__________________
Amir

 July 10, 2015, 04:30 property define #11 New Member   hassan Join Date: Jul 2015 Posts: 1 Rep Power: 0 hi my friends i want define kinetic viscosity for fluent by UDFs. but i am very weak in c programming. this is my equation: please help me/ thank you

 Tags define property, density, udf eror

 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 Sandilya Garimella FLUENT 0 May 19, 2008 12:35 Atsu FLUENT 4 April 22, 2006 15:04 Karthik FLUENT 6 December 8, 2004 19:19 AB CD-adapco 6 November 15, 2004 05:41 IKSOO FLUENT 2 December 8, 2002 21:37

All times are GMT -4. The time now is 11:50.

 Contact Us - CFD Online - Top