deformed hexa-mesh cells
 

Hi everybody,

I opened a new thread as I think that my problem is pretty specific.

I am meshing a 3D compressor blade for my bachelor thesis.
I am using an OCH-grid topology whereas the y+ value in the boundary layer of the blade has to be 0.0018(with a growth ratio of 1.1). This is a requirement which I definitley have to meet.

My problem is that Ansys deforms some of my hexas of the O-grid(directly the first cells on the balde surface) when I specify a wall distance lower than about 0.009 in a way which can be seen in the picture I loaded up. I absolutely do not understand what the reason for this problem is and I wanted to ask if somebody knows what the reason could be and how I can influence or correct it? All the associations of edges and vertices should actually be correct as the mesh is pretty good even one or two cells next to the location where the problem occurs(as can be seen in the picture)?!?

(The picture was taken at a wall distance of 0.004)


I hope I gave you all the key data needed to work on my problem. As I am quite new to the program and to the forum I want to apologize for any missing information. Please ask if you need more data or parameters.

Thank you very much for your help!



greets,
birnbaumm225

I solved the problem in the meantime.

It was a tolerance issue with the imported geometry(I imported the geometry from NX as .iges/.stp data-format). There were some locations around the blade, where the distance between the imported curve and the corresponding imported surface was bigger than what the y+ value was set to. Thus, the programm did not know whether to associate the mesh to the curve or to the surface. Therefore Ansys associated the mesh to the curve and in the nearest vicinity to the corresponding surface instead, so that the mesh was completely distorted.

What solved the problem, was to import the geometry in a larger measuring unit(in my case 25 times bigger) and scale it down to the needed(real) size. Additionally I decreased the tolerances in the Ansys Icem options, which also helped to enhance the visual display of the pre-mesh.

Sorry for the insufficient description of the problem, but like I already mentioned I am very new to the programm and to the forum also ;):rolleyes: