mass source
 

HI
I have a chamber, i want to keep the water level constant. I think, input fluid & output fluid should be equal. can i use mass source ( in meshing & geometry tab ) for negative flow rate? how ????

Yes, you can. The M/M source is defined w/ center on the origin, and normal vector facing up. Rotate and translate it so that it is on the floor where you want to withdraw fluid, still with normal vector pointing upward. Set the mass flow rate to a negative number.

The trick is to keep the m/m source always completely submerged at all times. If part of it is above the free surface, then the entire flow rate will not be removed. A uniform velocity is applied across the source, based on the source area and the desired mass flow rate. To have a uniform flow rate, all points on the m/m source must be submerged.

thank you so much dear JBurnham
. but my problem still is not solved. Can I have your email to send my simulation file?