Learning Forum

[anthony.bowers]

Hello, 

I recently upgraded fluent from R22 to R25 and my UDF (see below) continously crashes when I try to run it on the updated R25 Fluent? Does anyone know how to access gradients with R25? 

real hL ;

DEFINE_ADJUST(store_gradient, domain)

    {

    Thread *t;

    Thread **pt;

    cell_t c;

    real HL = 0.0;

    real Vol = 0.0;

    Domain *pDomain = DOMAIN_SUB_DOMAIN(domain,P_PHASE);

        /* IMPORTANT: Ensure temporary solver memory is retained:

            /solve/set/expert -> Keep temporary solver memory from being freed? yes

            See Ansys Knowledge base reference. */

    Alloc_Storage_Vars(pDomain,SV_VOF_RG,SV_VOF_G,SV_NULL);

    //allocate storage for scalar reconstructed and derivative.

    Scalar_Reconstruction(pDomain, SV_VOF,-1,SV_VOF_RG,NULL);

    Scalar_Derivatives(pDomain,SV_VOF,-1,SV_VOF_G,SV_VOF_RG,Vof_Deriv_Accumulate);

    mp_thread_loop_c (t,domain,pt)

    /*You can use FLUID_THREAD_P to check whether a cell thread is a fluid thread. The macro is passed

    a cell thread pointer t, and returns 1 (or TRUE) if the thread that is passed is a fluid thread, and 0

    (or FALSE) if it is not */

    if (FLUID_THREAD_P(t))

    {

        Thread *ppt = pt[P_PHASE];

        int zone_ID = THREAD_ID(ppt);

        if (zone_ID ==210)

        {

            begin_c_loop (c,t)

            {

                C_UDMI(c,t,0) = -C_VOF_G(c,ppt)[0];

                C_UDMI(c,t,1) = -C_VOF_G(c,ppt)[1];

                C_UDMI(c,t,2) = -C_VOF_G(c,ppt)[2];

                HL += (1-C_VOF(c,ppt))*C_VOLUME(c,t);

                Vol +=C_VOLUME(c,t);

                C_UDMI(c,t,30)=(1-C_VOF(c,ppt))/porosity;

                C_UDMI(c,t,31)=HL/(Vol*porosity);

            }

            end_c_loop (c,t)

        }

}

    Free_Storage_Vars(pDomain,SV_VOF_RG,SV_VOF_G,SV_NULL);

    Vol= PRF_GRSUM1(Vol);

    HL = PRF_GRSUM1(HL);

    hL = HL/(Vol);

}

[Rob]

It's probably a good idea to check the  Free_Storage_Vars(pDomain,SV_VOF_RG,SV_VOF_G,SV_NULL) and other macros are valid. If they're not in the manual they can (seemingly) randomly change between versions as data storage functions are altered. 

[Mark O]

The code may have changed slightly. The latest version of calc_vof_grad is in the customiozation manual, Example 3 for DEFINE_ADJUST at

https://ansyshelp.ansys.com/public/account/secured?returnurl=//Views/Secured/corp/v252/en/flu_udf/flu_udf_GeneralSolverDEFINE.html%23flu_udf_sec_define_adjust