I was having trouble obtaining reasonable solutions of pressure drop from Fluent. I created a very simple case of water flow in a circular pipe (files attached).
Pipe diameter: 1mm
Pipe length: 100 mm
Inlet velocity: 10 m/s
Water density 998.2 kg/m3; viscosity 0.001 Pa.s
Model: k-epsilon standard
It's a pretty straight forward case, and the pressure drop calculated by many empirical models would be about 160 kPa. I obtained similar numbers from CFX simulation and COMSOL simulation. Yet using Fluent, the result is about twice as big, i.e., ~300 kPa.
I tried several different cases and always got over-predicted pressure using Fluent. I also tried different mesh, yet didn't make it work.
This is a pretty straight forward case. I don't know where I might have problem. I guess I might have some very stupid rookie mistake somewhere.