[tofighi]

I want to model a simple water reservoir full of still water, with dimensions 1*1*1. Top of reservoir has atmospheric pressure, so the gauge pressure is assigned 0 there. I define the pressure inlet boundary condition at top of box and I specify the gravity accelaration -9.81 m/s2. I expect to get the static pressure at the bottom of box equal to 1000*9.81*1=9810 N/m2 but the results do not show this value. please recommend me the way I can model this problem.

[chaosh]

Fluent is a pain when it comes to hydrostatic pressure. The way you do it (and this works only for single phase incompressible flow) is this
1. Go to operating conditions and set operating density to 0
2. Go to the solver for pressure and pick body force weighted.

This should work.

SP