{"id":369456,"date":"2024-06-01T03:27:37","date_gmt":"2024-06-01T03:27:37","guid":{"rendered":"\/forum\/forums\/topic\/storing-and-plotting-values-in-udm\/"},"modified":"2024-06-01T03:27:37","modified_gmt":"2024-06-01T03:27:37","slug":"storing-and-plotting-values-in-udm","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/storing-and-plotting-values-in-udm\/","title":{"rendered":"Storing and plotting values in UDM"},"content":{"rendered":"

I basically want to store the value of r, for each face, and plot it vs axial position. When I try this, its just a constant line at 0. I turned on a udm location and node memery location but is there anything else I have to do?<\/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
    real radial_position;<\/div>\n
    real centroid[ND_ND];<\/div>\n
    int iter;<\/div>\n
 <\/div>\n
    begin_f_loop(f, t)<\/div>\n
    {<\/div>\n
        Ts = F_T(f, t);  \/\/ Current temperature at the face<\/div>\n
        heat = BOUNDARY_HEAT_FLUX(f, t);  \/\/ Heat transfer at face f in watts<\/div>\n
        F_AREA(Area, f, t);  \/\/ Get the area vector of the face<\/div>\n
        a_face = NV_MAG(Area);  \/\/ Magnitude of the face area<\/div>\n
 <\/div>\n
        \/\/ Calculate the radial position of the face centroid<\/div>\n
        F_CENTROID(centroid, f, t);<\/div>\n
        radial_position = centroid[1]; \/\/ Assuming the radial position is the y-coordinate in 2D axisymmetric<\/div>\n
 <\/div>\n
        \/\/ Heat flux for the circumferential area<\/div>\n
        heat_flux = (heat*2*M_PI*radial_position) \/ 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
\/\/ Store r in UDM<\/div>\n
        F_UDMI(f, t, 0) = r;  \/\/ Assuming the UDM index is 0<\/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-369456","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t