Grid quality in CFX4.2

P. Adamsen

I hope you can help me with me question. I have been running a test in CFX4.2 where I used a Poiseuille flow. I meshed the tube with an O-grid patched to an H-grid (i.e. Butterfly grid). But the numerical result deviates from the analytical fully developed profile in the block corners, where the two grids are patched together. This gets even more clear when I look at the velocity gradients for the same region.

And now to my question: Is this due to the fact that the control volumes contain a larger angle the closer one gets to the block corners, or is there some other explanation?