can user define a location dependent density in Define_property udf macro?

Pmaroul · January 18, 2019, 16:11

Hello all;

Can anyone describe me if the user is able to define the viscosity or density as a function of location by UDf writing in Define_proprties macro?

For example :

suppose :

$\rho =1000+0.00001x+0.00001y\$

How can the user implement this function in FLUENT?

Thanks a lot for any answer.

P.Maroul

pakk · January 21, 2019, 08:23

The Fluent manual shows how to make it depend on temperature. The example reads temperature as

Code:

real T = C_T(c,t);

If instead of temperature you want the coordinates, then just use the coordinate:

Code:

real xc[ND_ND];
C_CENTROID(xc,c,t);

Now, the x-coordinate is stored as xc[0], and the y-coordinate as xc[1]. So your equation would become

Code:

1000+0.00001*cx[0]+0.00001*cx[1]

Pmaroul · January 21, 2019, 16:34

Thank you Sir for your kind help.

That worked excellent.

Good Luck and best wishes.

January 18, 2019, 16:11	can user define a location dependent density in Define_property udf macro?	#1
Pmaroul Member Peter Maroul Join Date: May 2018 Posts: 52 Rep Power: 8	Hello all; Can anyone describe me if the user is able to define the viscosity or density as a function of location by UDf writing in Define_proprties macro? For example : suppose : $\rho =1000+0.00001x+0.00001y\$ How can the user implement this function in FLUENT? Thanks a lot for any answer. P.Maroul

January 21, 2019, 08:23		#2
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	The Fluent manual shows how to make it depend on temperature. The example reads temperature as Code: real T = C_T(c,t); If instead of temperature you want the coordinates, then just use the coordinate: Code: real xc[ND_ND]; C_CENTROID(xc,c,t); Now, the x-coordinate is stored as xc[0], and the y-coordinate as xc[1]. So your equation would become Code: 1000+0.00001cx[0]+0.00001cx[1]

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Time dependent sinus velocity inlet UDF	LinW	Fluent UDF and Scheme Programming	2	December 7, 2018 12:22
Missing math.h header	Travis	FLUENT	4	January 15, 2009 12:48
Errors running allwmake in OpenFOAM141dev with WM_COMPILE_OPTION%3ddebug	unoder	OpenFOAM Installation	11	January 30, 2008 21:30
UDF FOR UNSTEADY TIME STEP	mayur	FLUENT	3	August 9, 2006 11:19
DEFINE_DPM_OUTPUT macro UDF HELP	Puneet	FLUENT	3	November 28, 2003 11:55

January 21, 2019, 16:34		#3
Pmaroul Member Peter Maroul Join Date: May 2018 Posts: 52 Rep Power: 8	Thank you Sir for your kind help. That worked excellent. Good Luck and best wishes.