[Remusco]

Hello,
I am working in OpenFoam trying to compute the pressure drop in a piping system. The fluid is air, flowing at ~mach 0.5. I did write my own Python code to analytically solve this, but I want to validate it using CFD. When I try to solve this problem for a short length of pipe (~5 feet), the solver runs all night, and the residuals do not drop at all. What am I missing here? When I open the results in Paraview all I get is the same values for the pressure everywhere.

Physics model:

Steady-state
single phase
non-isothermal
viscous
RANS k-epsilon
Fluid: air
Pipe size: 76mm
Inlet volume flow rate: 1.055 m^3/sec
Inlet turbulence intensity: 2.92%
inlet length scale: 7mm
Outlet boundary: 100,000 Pa


Mesh:
Snappyhex mesh 8mm base size,
prism layers near boundary, 15mm total thickness, 15 cells, 1.1 expansion factor


I am a noob at cfd. I am probably missing something simple here.