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#1 |
New Member
Join Date: Jul 2013
Posts: 21
Rep Power: 13 ![]() |
Hello,
I am an user of FINE/Open. I would like to make a comparison with Fluent. Therefore, I need a little help in Fluent. In my domain, I have a fluid part and a solid part. In the solid, I'd like inserting a localized heat source in function of x, y and z. Is it possible? (and in the definition of the coordinates, it slightly exceeds? eg, due to an imprecise geometry, my x-coordinate exceeds of 1 mm, how Fluent work?) You can help me to construct the udf ? if I have this coordonates for the heat source : - x : x=0 to 0.001 - y : y=0 to 0.0015 - z : z=0.001 to 0.00012 vol=0.001*0.0015*0.0002; HS=10/vol; thanks a lot ! |
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#2 | |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,426
Rep Power: 49 ![]() ![]() |
Yes, defining a local heat source via UDF is possible. Here is part of a UDF I used for a similar purpose:
Code:
#include "udf.h" DEFINE_SOURCE(sourceterm,c,t,dS,eqn) { real x[ND_ND]; //some variable declaration real source; C_CENTROID(x,c,t); //reads the position of the cell centroid and writes it to the field x source = 1.0 //instead of the constant heat source, apply whatever function f(x[0],x[1]x[2],...) you need return source; //returns the value of the heatsource for the cell } The DEFINE_SOURCE macro used here loops automatically over all cells in the domain. Consequently, the source term is applied cell-wise which means it has a conatant value in a cell. I am sure you can work out the exact function using a few if-statements. x[0] holds the x-coordinate, x[1] the y-coordinate and x[2] the z-coordinate of the cell centroid. Edit: Quote:
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#3 |
New Member
Join Date: Jul 2013
Posts: 21
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Thank you ! The code is correct like this? (indeed, I made little mistake for the z coordinate)
#include "udf.h" DEFINE_SOURCE(sourceterm,c,t,dS,eqn) { real x[ND_ND]; real source; real vol; C_CENTROID(x,c,t); if(x[0]=>0 && x[0]<=0.001 && x[1]=>0 && x[1]<=0.0015 && x[2]=>0.001 && x[2]<=0.0012) { vol=0.001*0.0015*0.0002; source=10/vol; } else { source=0; } return source; } |
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#4 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,426
Rep Power: 49 ![]() ![]() |
Looks fine.
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#5 |
New Member
Join Date: Jul 2013
Posts: 21
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It's strange, I have no warning in the compilation, but the temperature in the solid doesn't increase. An idea?
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#6 | |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,426
Rep Power: 49 ![]() ![]() |
Quote:
Simply interpreting the UDF does not acrivate any source terms. source_term.jpg |
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#7 |
New Member
Join Date: Jul 2013
Posts: 21
Rep Power: 13 ![]() |
Yes yes, I find the error. I was stupid, I made a mistake in one of the coordinates. Thank you for your help !
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#8 |
New Member
David Aliaga
Join Date: Oct 2013
Posts: 4
Rep Power: 12 ![]() |
Hey hi! i have the same problem, i need to put on mi domain a constant heat, momentum and mass source on a localized point on the cell zone ( in this case water liquid). Cause of the options of Fluent it self only allows to loop the source on all the fluid cell zone, i realized that i haved to find the way to program with UDF to indicate just a certain point, in this case the centroid of the cell. I also intempted to make two bodies and assign the fluid zone to both, but the all turns real messy with the zones that are created. My question is, this udf will help me with my problem? wich are the steps for writing my udf. IŽll really appreciated your help =D
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