Help! -User Difined Functions----Drag Coefficient
 

Hi,

I am using Eulerian Model for multiphase flow. In the model, the drag coefficient is 1.0. And I defined the UDF of Drag coefficient as follows:

#include "udf.h"

DEFINE_EXCHANGE_PROPERTY(drag, cell, x_thread, s, f) { Cd = 1.0; return Cd; }

When the UDF is interpreted, Fluent says "Cd" is an undeclared variable. Even if I declare Cd is a real later, Fluent still showed me the same message.

Could someone help me?

Thank you.

Re: Help! -User Difined Functions----Drag Coeffici
 

Cd is a variable, and you must define it *before* you use it.

Usually, it's a good idea to define variables as local, in order to use them only when needed:


DEFINE_EXCHANGE_PROPERTY(drag, cell, x_thread, s, f)
{
real Cd
Cd = 1.0;
return Cd;
}


or, easier:


DEFINE_EXCHANGE_PROPERTY(drag, cell, x_thread, s, f)
{
return 1.0;
}


Hi :)

ap

Re: Help! -User Difined Functions----Drag Coeffici
 

Thanks AP, I will try as you advised. Colin

Re: Help! -User Difined Functions----Drag Coeffici
 

I forgot a semicolon in this line, in my first function:

real Cd;

sorry

Hi :)

ap

Re: Help! -User Difined Functions----Drag Coeffici
 

Hi, ap, they work! Thanks.

Re: Help! -User Difined Functions----Drag Coeffici
 

Great.

Hi :)

ap