Help on simulation domain

Derek Jing

Hi all,

Now I am going to model following problem: A hopper is fully loaded with small sands. The sands will flow download, go through the hopper orifice and finally fall into a tank below the hopper. The simulation will stop after all sands have flowed out of the hopper. The main result I hope to obtain is the mass flow rate through thre hopper orifice.

Now my question is: Shall my simulation domain only include the hopper itself, or include both the hopper and the tank? If I use the former, the sand mass in my domain will be less and less. If I use the later, the mass in the domain will be constant. I prefer to use the former choice, but I am not sure whether it is correct.

Can you give me some advice on using which domain? Your help is greatly appreciated.

-Derek