specified density Fluent
 

Hi

I have made a simulation in a vertical pipe including gravity for axis Y (-9.81m/s2). Now I have obtained different static pressure (higher in the point which has less height and lower in the point which has more height). After measure static pressure with fluent when I consider the different height between the 2 points I obtain the same head losses than a horizontal pipe.

In spite of this, I have a question about specified operating density option. When you choose gravity you can choose a specified operating density option. In several tutorial says that you can choose 0 kg/m3 as density but I do not understand why I can not use the density of water. Ihave used velocity inlet and outflow as boundary conditions.

Which is the influence of specified operating density?. If I choose 0 kgm3 I obtain a difference static pressure between 2 points which is not the same as my head losses. On the other hand If I do not choose anything density the difference static pressure is the same as my head losses: Why?

Thanks