Comparison between the results obtained and the theoryHereunder, we can see the results given by the former calculation. They looks good. Indeed, it appears the hyperbolic shape, and the values of the speed on the boundary are coherent.
Nevertheless, by comparing the numerical results to the theoretical ones, it appears they are not as accurate as they could. Indeed, whereas the qualitative aspect is respected, the quantitative results are not excellent. The numerical results always under-estimate the velocity.
We have in red the numerical results, in blue the theoretical points and in yellow, the wall values, computed for the inner cylinder and zero for the outer cylinder.