Static Pressure Question
 

Hello,

I am modelling a laminar incompressible flow in the S pipe. The inlet velocity is quite small, generating Re=500, pressure outlet = 1 atm. Initial condition is P=1 atm. Why the static pressure is larger at the inlet than the outlet? Is this because the velocity at inlet is lower than outlet so Bernoulli's equation calculated a larger static pressure? Is my understanding correct?


The pressures I defined in the beginning is the static pressure or total pressure?


I need your help ! Thanks !

[IMG]http://s22.postimg.org/a2u8rer4t/QQ_20151029233830.jpg[/IMG]

[IMG]http://s22.postimg.org/7mx0rayfx/QQ_20151030000457.jpg[/IMG]

If you are specifying velocity at the inlet and a static pressure at the outlet then then I would expect the static pressure to be high to drive the flow through the outlet.

Hi, thanks a lot for your reply. I just wander how the solver calculate the static pressure higher at inlet than outlet since I define the initial condition is 1 atm, same as outlet. Is this 1 atm the static or total pressure?

As you said it is just an initial condition. Your initial conditions gets washed way as your simulation progresses. Initial conditions should not affect your end solution for a continuous flow problem (You might get convergence issues if they are set really bad).

you must have a pressure gradient to have velocity (i.e. flow).