[mm66]

Hi Foamers,

recently, I have been working on some 3D 90 degree bends. I investigated two cases:

1: With constant diameter D1 (from inlet to outlet which means inlet pipe of D1, 90 degree bend of D1, then outlet pipe of D1)
2: With bigger diameter (D2>D1) at the inlet, then reducing to the same diameter at the outlet (which means inlet pipe of D2, 90 degree bend of D2, reducer from D2 to D1 after the bend, then outlet pipe of D1)

I expected the second geometry to have lower pressure drop; however, simulation results are showing opposite of that...

Some details: simpleFoam, incompressible, turbulent (tried kEpsilon, realizableKE, kOmegaSST all giving similar answers), used wall functions.

Any ideas would help...

Thanks