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

Pmaroul · January 18, 2019, 15:11

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, 07:23

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, 15:34

Thank you Sir for your kind help.

That worked excellent.

Good Luck and best wishes.

January 18, 2019, 15:11	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: 7	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, 07:23		#2
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	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]

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January 21, 2019, 15:34		#3
Pmaroul Member Peter Maroul Join Date: May 2018 Posts: 52 Rep Power: 7	Thank you Sir for your kind help. That worked excellent. Good Luck and best wishes.