[knuckles]

I am trying to do LES of a circular turbulent jet in OpenFOAM. My simulation almost immediately predicts that the velocity and pressure fields have "bands" as shown in the attached image.


My mesh is kind of like a diverging cylinder and checkMesh seems to think it is good (max aspect ratio ~20, max non-orthogonality ~27). My boundary conditions are :

• Inlet: turbulentInlet for velocity and zeroGradient for pressure
• Outlet: fixedValue for pressure and inletOutlet for velocity
• Sides: waveTransmissive for p and fixedValue for U. I've tried other boundary conditions for p on the sides, but they seem to cause pressure waves to reflect all over the place and trigger instability.

My schemes are second order in time and space and I'm using PIMPLE with 2 outer correctors, 2 correctors, 2 non-orthogonal correctors, and no momentumPredictor.



Anyone have any ideas what I'm doing wrong?