[alinik]

Hi all,

Apparently wall distance macro, C_WALL_DIST, is not available anymore and we cannot use it in a UDF.
Is there any alternative to that?

Thanks,
Ali

[alinik]

It seems that it is available. It just has to be filled first.
I received a UDF from a friend indicating how to do that.
I do not fully understand this code and how to use it. An help in understanding this would be greatly appreciated.

#include "udf.h"
#include "prox.h"

static cxboolean wall_dist_set = FALSE;

DEFINE_ON_DEMAND(set_wall_dist_udm0)
{
#if !RP_HOST

Domain *domain;
Thread *t;
cell_t c;

if (! wall_dist_set)
{
domain = Get_Domain(ROOT_DOMAIN_ID);

Alloc_Storage_Vars(domain, SV_RTMP_0, SV_NULL);

Calc_Cell_Wall_Distance_New(domain, SV_RTMP_0);

thread_loop_c(t,domain)
{
begin_c_loop(c,t)
{
C_UDMI(c,t,0) = C_TMP0(c,t);
}
end_c_loop(c,t)
}

wall_dist_set = TRUE;
}
#endif /* !RP_HOST */
}

DEFINE_ON_DEMAND(reset_udm0)
{
#if !RP_HOST

Domain *domain;
Thread *t;
cell_t c;

domain = Get_Domain(ROOT_DOMAIN_ID);

thread_loop_c(t,domain)
{
begin_c_loop(c,t)
{
C_UDMI(c,t,0) = 0.0;
}
end_c_loop(c,t)
}

#endif /* !RP_HOST */

wall_dist_set = FALSE;
}

[LuckyTran]

I remember this being a very old issue that came up several years ago and you should be able to search for several examples. I believe you run into a segmentation fault because the macro depends on specific variables being declared that Fluent does not allocate automatically. Thus, the fix is to force Fluent to calculate the wall distance on-demand using some form of user-defined memory.