{"id":368405,"date":"2024-05-24T01:37:25","date_gmt":"2024-05-24T01:37:25","guid":{"rendered":"\/forum\/forums\/topic\/udf-works-in-planar-option-but-not-axisymmetric\/"},"modified":"2024-05-24T01:37:25","modified_gmt":"2024-05-24T01:37:25","slug":"udf-works-in-planar-option-but-not-axisymmetric","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/udf-works-in-planar-option-but-not-axisymmetric\/","title":{"rendered":"UDF works in planar option but not axisymmetric"},"content":{"rendered":"

My udf works when I select the planar option, even with an axis BC, but when I select axisymmetric, the heat flux is 10x higher than expected. I only want the heat flux radial direction (y direction), which is maybe why.<\/p>\n

 <\/p>\n

#include “udf.h”<\/div>\n
#include <math.h><\/div>\n
 <\/div>\n
#define rho 950 \/\/ kg\/m^3<\/div>\n
#define Hg 2033631 \/\/ J\/Kg<\/div>\n
#define Hf -310000 \/\/ J\/Kg<\/div>\n
#define T_ref 298 \/\/ K<\/div>\n
#define A1 0.01104 \/\/ m\/s<\/div>\n
#define A2 3.9648 \/\/ m\/s<\/div>\n
#define Cp 1500 \/\/ J\/(Kg*K)<\/div>\n
#define E1 20557.188 \/\/ J\/mol<\/div>\n
#define E2 55893.78 \/\/ J\/mol<\/div>\n
#define R_u 8.314 \/\/ J\/(mol*K)<\/div>\n
#define alpha 0.3<\/div>\n
 <\/div>\n
DEFINE_PROFILE(surface_temperature_profile, t, position)<\/div>\n
{<\/div>\n
    face_t f;<\/div>\n
    real Ts, heat_flux, heat, a_face, Hv, r, Ts_old, Ts_new, error, Ts_new_prime, Area[ND_ND];<\/div>\n
    int iter;<\/div>\n
    begin_f_loop(f, t)<\/div>\n
    {<\/div>\n
        Ts = F_T(f, t);  \/\/ Current temperature at the face<\/div>\n
        printf(“Temp of face %d: %g K\\n”, f, Ts);<\/div>\n
        heat = BOUNDARY_HEAT_FLUX(f, t);  \/\/ Calculating the heat flux at face f in watts<\/div>\n
        F_AREA(Area, f, t);<\/div>\n
        a_face = NV_MAG(Area);<\/div>\n
        heat_flux = heat \/ a_face; \/\/ Heat flux in W\/m^2<\/div>\n
        printf(“Heat flux on face %d: %g W\/m^2\\n”, f, heat_flux);<\/div>\n
        Ts_old = Ts;<\/div>\n
        iter = 0;<\/div>\n
        error = 1;<\/div>\n
        while (error > 1e-6 && iter < 100)<\/div>\n
        {<\/div>\n
            Hv = Hg – Hf + Cp * (Ts – T_ref);  \/\/ Calculation heat of formation<\/div>\n
            r = (fabs(heat_flux)) \/ (Hv * rho);  \/\/ Regression rate<\/div>\n
            if (Ts_old > 722)<\/div>\n
            {<\/div>\n
                Ts_new = E1 \/ (R_u * (log(A1) – log(r)));  \/\/ New surface temperature for high temperature<\/div>\n
            }<\/div>\n
            else<\/div>\n
            {<\/div>\n
                Ts_new = E2 \/ (R_u * (log(A2) – log(r)));  \/\/ New surface temperature for low temperature<\/div>\n
            }<\/div>\n
            error = fabs(Ts_new – Ts_old);  \/\/ Error calculation<\/div>\n
            Ts_old = Ts_new;  \/\/ Update Ts_old for next iteration<\/div>\n
            iter++;  \/\/ Increment iteration count<\/div>\n
        }<\/div>\n
 <\/div>\n
        Ts_new_prime = Ts + (alpha * (Ts_new – Ts)); <\/div>\n
r = (fabs(heat_flux)) \/ (Hv * rho);<\/div>\n
        printf(“New Temp %d: %g K\\n”, f, Ts_new_prime);<\/div>\n
        printf(“r_dot %d: %g mm\/s\\n”, f, r*1000);<\/div>\n
        F_PROFILE(f, t, position) = Ts_new_prime;  \/\/ Update the face temperature profile<\/div>\n
    }<\/div>\n
    end_f_loop(f, t)<\/div>\n
}<\/div>\n","protected":false},"template":"","class_list":["post-368405","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["343144","15180"],"_bbp_author_ip":["184.24.96.207"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["218"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["368405"],"_bbp_forum_id":["27792"],"_bbp_engagement":["15180","343144"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["374025"],"_bbp_last_active_id":["374025"],"_bbp_last_active_time":["2024-07-29 14:19:21"]},"test":"zwernjaydengmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/368405","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/368405\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=368405"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}