[stix]

Hi!

I am new to OpenFOAM and I have to use OpenFOAM for my diploma thesis. I want to compare the results of OpenFOAM with simple examples, which can be calculated by hand. My first example is a straight pipe flow and i already have problems. My geometry is a 1mx1m quadratic tunnel with a length of 20m. I defined all boundary conditions (inlet 5 m/s, outlet pressure=0, wall ). The flow is turbulent and i use the komegaSST model for the turbulence. i simulated the flow with different mesh resolutions (various y+). The y+ values i were 30, 50, 100, 150.

Now the problem is that i calculated the pressure loss analytically and the OpenFOAM results aren't even near the exact results. They are 30% (and for high y+ values even more) away from the exact results.

Could anybody please help me with my problem?

Thanks, Daniel

[rpberlin]

I can think of a few reasons why your pressure drop is too high.

Are you using fully-developed flow in your analytical calculations and are you specifying a flat velocity profile at the inlet?

Otherwise, can you show a couple of pictures of your mesh and your results?