{"id":398407,"date":"2024-12-24T07:40:58","date_gmt":"2024-12-24T07:40:58","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/trial-start-of-udf-for-getting-yplus-at-all-cells\/"},"modified":"2024-12-24T07:40:58","modified_gmt":"2024-12-24T07:40:58","slug":"trial-start-of-udf-for-getting-yplus-at-all-cells","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/trial-start-of-udf-for-getting-yplus-at-all-cells\/","title":{"rendered":"Trial start of UDF for getting yplus at all cells"},"content":{"rendered":"

<div>#include “udf.h”<\/div><p><br><br><\/p><div>real get_yplus(cell_t c, Thread* t, Domain* domain)<\/div><div>{<\/div><div>    \/\/ Declaration<\/div><div>    real result, cell_x_value, face_x_value, shear;<\/div><div>    real cell_centroid[ND_ND];<\/div><div>    real NV_VEC(face_centroid);<\/div><div>    face_t f;<\/div><p> <\/p><div>    shear = 10;<\/div><div>    C_CENTROID(cell_centroid, c, t);<\/div><div>    cell_x_value = cell_centroid[0];<\/div><p> <\/p><div>    thread_loop_f(t, domain)<\/div><div>    {<\/div><div>        begin_f_loop(f, t)<\/div><div>        {<\/div><div>            if ((BOUNDARY_FACE_THREAD_P(t)) && (THREAD_TYPE(t) == THREAD_F_WALL))<\/div><div>            {<\/div><div>                F_CENTROID(face_centroid, f, t);<\/div><div>                face_x_value = face_centroid[0];<\/div><div>                if (cell_x_value == face_x_value)<\/div><div>                {<\/div><div>                    shear = 1;<\/div><div>                }<\/div><div>            }<\/div><div>        }<\/div><div>        end_f_loop(f, t)<\/div><div>    }<\/div><p> <\/p><div>    return shear;<\/div><div>}<\/div><p><br><br><\/p><div>DEFINE_ADJUST(yplus, domain)<\/div><div>{<\/div><div>    Thread* t;<\/div><div>    cell_t c;<\/div><div>    face_t f;<\/div><p> <\/p><div>    \/* Fill UDS with the variable. *\/<\/div><div>    thread_loop_c(t, domain)<\/div><div>    {<\/div><div>        begin_c_loop(c, t)<\/div><div>        {<\/div><div>            C_UDSI(c, t, 0) = get_yplus(c, t, domain);<\/div><div>        }<\/div><div>        end_c_loop(c, t)<\/div><div>    }<\/div><p> <\/p><div>    thread_loop_f(t, domain)<\/div><div>    {<\/div><div>        if (THREAD_STORAGE(t, SV_UDS_I(0)) != NULL)<\/div><div>        {<\/div><div>            begin_f_loop(f, t)<\/div><div>            {<\/div><div>                if (BOUNDARY_FACE_THREAD_P(t))<\/div><div>                {<\/div><div>                    F_UDSI(f, t, 0) = 0;<\/div><div>                }<\/div><div>                else<\/div><div>                {<\/div><div>                    F_UDSI(f, t, 0) = ((get_yplus(F_C0(f, t), THREAD_T0(t), domain) + get_yplus(F_C1(f, t), THREAD_T1(t), domain)) \/ 2);<\/div><div>                }<\/div><div>            }<\/div><div>            end_f_loop(f, t)<\/div><div>        }<\/div><div>    }<\/div><div>}<\/div><div> <\/div><div>This UDF returns 10 only at all cell centres that is the internal face thread loop did not matched for any cell. Can anyone point what could be the logical flaw in the get_yplus function.<br>This is a 2D axisymmetric pipe, with a constant heat flux at the wall.<\/div><\/p>\n","protected":false},"template":"","class_list":["post-398407","topic","type-topic","status-publish","hentry","topic-tag-cfd-udf-fleunt","topic-tag-fluent","topic-tag-yplus"],"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