[ho3ein.agl]

hi

is it possible use define macro like this:

DEFINE_DELTAT(mydeltat, domain)
{
.
.
.
DEFINE_ON_DEMAND(on_demand_calc)
{

......

}
.
.
.
}

[gearboy]

Absolutely impossible.

Originally Posted by ho3ein.agl

hi

is it possible use define macro like this:

DEFINE_DELTAT(mydeltat, domain)
{
.
.
.
DEFINE_ON_DEMAND(on_demand_calc)
{

......

}
.
.
.
}

[ho3ein.agl]

I need to find max temp in DEFINE_DELTAT's commands.
do u have any idea?

[gearboy]

Originally Posted by ho3ein.agl

I need to find max temp in DEFINE_DELTAT's commands.
do u have any idea?

Just loop over all the cells in your DEFINE_DELTAT macro.

[ho3ein.agl]

So why in Fluent UDF manual used DEFINE_ON_DEMAND to find max Temp?

/**********************************************************************
UDF to calculate temperature field function and store in
user-defined memory. Also print min, max, avg temperatures.
***********************************************************************/
#include "udf.h"
DEFINE_ON_DEMAND(on_demand_calc)
{
Domain *d; /* declare domain pointer since it is not passed as an
argument to the DEFINE macro */
real tavg = 0.;
real tmax = 0.;
real tmin = 0.;
real temp,volume,vol_tot;
Thread *t;
cell_t c;
d = Get_Domain(1); /* Get the domain using ANSYS Fluent utility */
/* Loop over all cell threads in the domain */
thread_loop_c(t,d)
{
/* Compute max, min, volume-averaged temperature */
/* Loop over all cells */
begin_c_loop(c,t)
{
volume = C_VOLUME(c,t); /* get cell volume */
temp = C_T(c,t); /* get cell temperature */
if (temp < tmin || tmin == 0.) tmin = temp;
if (temp > tmax || tmax == 0.) tmax = temp;
vol_tot += volume;
tavg += temp*volume;
}
end_c_loop(c,t)
tavg /= vol_tot;
printf("\n Tmin = %g Tmax = %g Tavg = %g\n",tmin,tmax,tavg);
/* Compute temperature function and store in user-defined memory*/
/*(location index 0) */
begin_c_loop(c,t)
{
temp = C_T(c,t);
C_UDMI(c,t,0) = (temp-tmin)/(tmax-tmin);
}
end_c_loop(c,t)
}
}

[upeksa]

DEFINE_DELTAT is used to define the time step in transient calculations.
DEFINE_ON_DEMAND is used mainly for post process purposes, for example, to show the contours of a used defined function such as (temp-tmin)/(tmax-tmin).

[ho3ein.agl]

thanks

I will try your suggestion

[ho3ein.agl]

my udf is:

Red number is line number in udf commands .

DEFINE_DELTAT(mydeltat, domain)
{
	real time_step;
	real T_max=0.0 ;
	real T1=303.0 ;
	real T2=300.5 ;
	real T3=304.0 ;
	Thread t;
    cell_t c;
54	thread_loop_c(t,domain)
	{
56		begin_c_loop(c,t)
		{
58			temp = C_T(c,t);
			if (temp > T_max || T_max == 0.0) T_max = temp;
		}
		end_c_loop(c,t)
	}
	if (T_max < T1) time_step = 1.0;
	else time_step = 0.00001;
	return time_step;
}

error after build in compiler window:

Done.

(chdir "libudf")(chdir "win64\2ddp")# Generating ud_io1.h
Paper_PCM_Prop_and_DeltaT_v2.c
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(54) : error C2440: '=' : cannot convert from 'thread_struct *' to 'Thread'
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(54) : error C2088: '!=' : illegal for struct
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(54) : error C2232: '->next' : left operand has 'struct' type, use '.'
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(56) : error C2232: '->nelements' : left operand has 'struct' type, use '.'
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(58) : error C2232: '->storage' : left operand has 'struct' type, use '.'

Done.

whats wrong in udf?

[gearboy]

"Thread t;" should be "Thread *t;", and temp must be declared before use.

Originally Posted by ho3ein.agl

my udf is:

Red number is line number in udf commands .

DEFINE_DELTAT(mydeltat, domain)
{
    real time_step;
    real T_max=0.0 ;
    real T1=303.0 ;
    real T2=300.5 ;
    real T3=304.0 ;
    Thread t;
    cell_t c;
54    thread_loop_c(t,domain)
    {
56        begin_c_loop(c,t)
        {
58            temp = C_T(c,t);
            if (temp > T_max || T_max == 0.0) T_max = temp;
        }
        end_c_loop(c,t)
    }
    if (T_max < T1) time_step = 1.0;
    else time_step = 0.00001;
    return time_step;
}

error after build in compiler window:

Done.

(chdir "libudf")(chdir "win64\2ddp")# Generating ud_io1.h
Paper_PCM_Prop_and_DeltaT_v2.c
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(54) : error C2440: '=' : cannot convert from 'thread_struct *' to 'Thread'
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(54) : error C2088: '!=' : illegal for struct
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(54) : error C2232: '->next' : left operand has 'struct' type, use '.'
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(56) : error C2232: '->nelements' : left operand has 'struct' type, use '.'
..\..\src\Paper_PCM_Prop_and_DeltaT_v2.c(58) : error C2232: '->storage' : left operand has 'struct' type, use '.'

Done.

whats wrong in udf?