Hi everyone, I am running a circular pipe flow simulation in OpenFoam, and I found an unexpected circumferential non-uniformity in the results. The case should be axisymmetric, but when I unfold the pipe wall and plot the wall shear stress, I get clear periodic vertical stripe patterns in the circumferential direction. At first I thought the problem might come from my own wall shear stress calculation, but then I checked the turbulence fields and found that omega and k show a very similar regular circumferential pattern. I am thinking that this may be related to the mesh or the fvSchemes that i used: ddtSchemes { default steadyState; } gradSchemes { default cellLimited leastSquares 1; } divSchemes { div(phi,U) bounded Gauss upwind; turbulence bounded Gauss upwind; div(phi,k) $turbulence; div(phi,omega) $turbulence; div(phi,epsilon) $turbulence; div(phi,e) $turbulence; div(phi,h) $turbulence; div(phi,K) $turbulence; div(phiOverRho,omega) $turbulence; div(phiOverRho,epsilon) $turbulence; div(phiOverRho,k) $turbulence; } laplacianSchemes { default Gauss linear corrected; } interpolationSchemes { default linear; } snGradSchemes { default corrected; } Any suggestions on how to diagnose or eliminate this circumferential non-uniformity would be greatly appreciated. Thanks! https://cdn.discordapp.com/attachments/400697259819270145/1524626029304479864/image.png?ex=6a506e23&is=6a4f1ca3&hm=af42c0b31d07643a4326148eb65ff7f30b1b517cc860abe660b0692cacca40c9& https://cdn.discordapp.com/attachments/400697259819270145/1524626029862457484/image.png?ex=6a506e23&is=6a4f1ca3&hm=3daa824486031ff97b932433f2dd42b48dead894f5521f1338a3c2fd31308558& https://cdn.discordapp.com/attachments/400697259819270145/1524626030525022278/image.png?ex=6a506e23&is=6a4f1ca3&hm=59bd9b72a6ca11243b629b499b8989f9d6237472a79ba671049a7d517df198af& https://cdn.discordapp.com/attachments/400697259819270145/1524626031191920780/image.png?ex=6a506e24&is=6a4f1ca4&hm=84939ab5f373dff7229d93cbc00e9c0a21fc0b9c673845e6b29f95aa0ab84721&