Learning Forum

[Alex Chiella]

Hi Rob! Always excited to get replies from you!

The square at the top is the symmetry cross-section of an air cylinder, that I set as an atmospheric (0 Pa gauge) pressure outlet. I am using the symmetry conditions on a halved domain.
I have a mass-flow inlet with a very low mass flowrate, which results in ~10m/s at the 50mm pipe inlet.
The solution seems to have converged alright, I mostly checked mass balance during iterations and the static pressure contour. Very mild static pressure differences through the whole domain by the way.
The hydrogen flow is exiting through that outlet at about 5m/s at normal conditions, a pretty ordinary scenario. 
As I said, this is a sort of y-elbow pipe, with an inlet, an outlet (pictured) and a vacuum-entrainment opening. For this given flowrate there's not much going on at the entrainment opening, so the outflow might be compared to a gaseous stream going through an elbow at low velocity.

This is what I get from Y velocity coloured symmetry plane pathlines, so the flow is indeed being pushed back to the ground.

I do know that light gas plumes tend to have a boost in Y velocity while dense ones are bent down, but I struggled finding more stuff about that online.