{"id":348207,"date":"2024-02-01T10:37:19","date_gmt":"2024-02-01T10:37:19","guid":{"rendered":"\/forum\/forums\/topic\/ddpm-remove-partciles-via-udf\/"},"modified":"2024-02-01T10:37:19","modified_gmt":"2024-02-01T10:37:19","slug":"ddpm-remove-partciles-via-udf","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ddpm-remove-partciles-via-udf\/","title":{"rendered":"DDPM – remove partciles via UDF"},"content":{"rendered":"

Hi,<\/p>\n

i am modelling particles falling through a 3D-geometry with a gas flow from the bottom using DDPM (ANSYS 2021 R2). I want to remove the particles at a certain height using a UDF:<\/p>\n

DEFINE_DPM_SCALAR_UPDATE(remove_particles, cell, thread, initialize, tp)
{<\/p>\n

real y_lim_out=1.1;                
if (TP_POS(tp)[1]<y_lim_out) {
        Message(”            PARTICLE ID %d REMOVED FROM DOMAIN\\n”, tp->part_id);
        tp->stream_index = -1;
        }
}<\/p>\n

This works well when looking at the particle tracks (left): there are no particles below the specified height (red line). However, when looking at the contours of vol. fraction of the solid phase (right), it seems like FLUENT is still showing a vol. fraction >0 below the specified height.<\/p>\n

<\/p>\n

According to the Theory Guide 2021R2 (14.5.23. Dense Discrete Phase Model), the solution for the solid phase, such as volume fraction or velocity field, is taken from the Lagrangian tracking solution. Why is there a solid vol. fraction at the very bottom where all particles have been removed?<\/p>\n

Thanks a lot in advance,<\/p>\n

Lukas<\/p>\n","protected":false},"template":"","class_list":["post-348207","topic","type-topic","status-closed","hentry","topic-tag-multiphase_models-1","topic-tag-ddpm","topic-tag-fluent","topic-tag-remove-particles-1","topic-tag-udf"],"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\n\t\t\n\t\t\n\t\t