Hi sdeb
Thanks for you answer. As a new to UDF, I tried the idea of particle loop based on the Fluent Customization Manual's example, the udf tested is shown below. Surprisingly, the contour output of UDM results is always 0. Could you please provide more information about your idea?
Then, besed on my tests of comparison between "C_UDMI(c,t,0)+=C_VOLUME(c,t)"and"C_UDMI(c,t,0)=C_VOLUME(c,t)" in the "DEFINE_DPM_SCALAR_UPDATE( ParticleCon,c,t,initialize,tp)", the "C_UDMI(c,t,0)+=..." can successfully tracking the particles in every cell and display the gradient-changing contour,in which the inlet position is highest because more particles passed with the same cell volume. Hovever, it still exists the cumulative issues described in question. Due to the "0" resul of the particle loop method, i still couldn't try more parctices to validate its effectiveness.
Thank you again for your enthusiastic reply.Looking forward to more ideas from you.