# XFLR5 vs CFD **URL:** https://www.simscale.com/forum/t/xflr5-vs-cfd/82854 **Category:** Using SimScale **Created:** [July 29, 2018, 8:53pm UTC](https://www.simscale.com/forum/t/xflr5-vs-cfd/82854 "2018-07-29T20:53:21Z") **Posts on this page:** 1 **Showing post:** 22
### Author: ![DaleKramer](https://www.simscale.com/forum/user_avatar/www.simscale.com/dalekramer/32/20201_2.png) [@DaleKramer](https://www.simscale.com/forum/u/DaleKramer) #### Post date: [August 2, 2018, 9:36am UTC](https://www.simscale.com/forum/t/xflr5-vs-cfd/82854/22 "2018-08-02T09:36:50Z")
Darren @1318980, Now this is worth a new post… So I look at the top planform view of the Mesh 3 at the y=-37.7 start of planform taper into another surface and I have an AHA moment: ![AHA-redzones](https://www.simscale.com/forum/uploads/default/original/3X/a/f/af6108ac5cc0bcf2294465261d424b8b6f2ab012.JPG) As you probably know I have an active Topic about 2 issues I am having with Feature and Surface Refinements. The cause of the yPlus discontinuities in the above image is [Issue #2 at this post](https://www.simscale.com/forum/t/feature-refinement-not-working-as-expected-2-issues/82871/2). I do not think the layering algorithm can handle that angular jaggy causing the layers to deflate there. The mesh jaggies at this surface/surface edge intersection as seen above are Issue #2 exactly. I have tried to reduce the effect of Issue #2 in my mesh by simply refining all the way to Level 11 (overkill I think but had to due to Issue #2). Unfortunately, there are still jaggies even at Level 11 and this is one of them, If I go to a Feature Refinement these ‘step changes of leading edge planform angles’ at the wing ‘ribs’ will also be refined at Level 11 but at a cost of a larger mesh size (a temporary solution at best until Issue is fixed 😉). Also, if you look closely at the leading edge joint in the mesh, even at Level 11 there is still small jaggies, which I believe is causing a lot of the small leading edge red zones in the yPlus planform mapping. I will try the bandaid Feature Refinement and report back… Dale --- _[View the full topic](https://www.simscale.com/forum/t/xflr5-vs-cfd/82854)._