[DUYH961122]

A Question of VOF-to-DPM model in Fluent 2021
Hello everyone,
I'm pretty new to fluent. Recently, I've been trying to use VOF-to-DPM model to simulate my question. But I have run into a problem I couldn't solve.

The simulation is metal liquid breakup in airflow (v_metal=3.29m/s, v_air=100m/s). I'm using the sharp VOF model and implicit body forces, realizable k-e turbulence model and VOF-to-DPM model (refinement threshod 0.05, coarsening 0.01, based on unscaled metal VOF curvature, updating every 5 time-step). And the refinement level is 4. Initail grid mesh were 3mm.

The result is shown in picture.

It looks great, but I'm comfused that some particels came together and this particels's diameter were same. Besides, when I see the video of breakup progress, the particle swarms suddenly appeared.

Has anyone experienced similar problem? Why the particel swarms will appear? And is it my seting problem?

Thanks in advance