I need to calculate a system where a gas is injected into a large space through a pipe. The gas pressure is higher than the ambient, what happens when the gas leaves the pipe, I would assume that the gas pressure is decreased to the ambient pressure and the density decrease and velocity increase. Is that correct and what is the correct way of modelling such a system.

I do not want to model the pipe system but just include the outlet of the pipe, but which velocity should then be used?

The velocity based on the density calculated from the real gas pressure or the velocity based on that the gas pressure is equal to the ambient pressure.

What happens if it is an incompressible fluid, i.e. water

Thanks in advance Newbie

Q:Is that correct

A: Yes

Q:what is the correct way of modelling such a system

A:That depends on what you are looking for.

Q:but which velocity should then be used

A:That depends on diameter and pressure.

Q:The velocity based on the density calculated from the real gas pressure or the velocity based on that the gas pressure is equal to the ambient pressure

A: If you are looking for tha velocity of the fluid, you need to know the pressure difference between the gas pressure and the amb. pressure.

Q:What happens if it is an incompressible fluid, i.e. water

A: Happens to what ?

Try explaining your problem with more details, ie. what you are looking for ect.