nHi Rob,nThank you for your response.nComparing with the Literature, for Reynold's Number = 13000, with turbulence intensity of <0.06%, the Cd value for Square is close to ~2.1 . I am simulating under the same conditions and I get around ~1.7nThis mesh's first cell height is 0.01 m (D/10), I tried running with 0.005 m (D/20), a little finer mesh, but it didn't really change much.nI have run a D/1000 mesh (first cell height = 0.0001 m) but it is too computationally expensive and the results have no order (I ran for just 4 seconds though, took me 3 days). Y+ was very low for this case, close to 1. n