[fomalhaut]

Hello everyone, I am struggling with a compressor blade that i need to mesh. I extruded the 2D blocks I had into 3D by setting a certain thickness. In the fore part of the blade I had an unstructured mesh obtained thanks to a free block.

Now I moved into 3D and I added a small triangular surface to the blade. I do not know how to associate it properly in a way that the unstructured mesh would follow the "triangles". Is it possible in some ways?

Attached some pictures. Notice how the mesh in the fore region was in 2D for the baseline blade. This section has been cut where actually there is the triangular shape, showing n evidence that it is able to follow that surface.

Matteo

[DarylMusashi]

Dear Matteo,

just from curiosity: What is the purpose of these triangles near the leading edge?

I have no idea which meshing software you use and I certainly never used this, but the main problem might be that these triangles do not cover the whole height of the blade (a coordinate system would be helpful). Referring to your picture 1: Are the triangles meshed correctly, when they reach completely from bottom to top?

You extruded the 2D block to a 3D block over the complete height. Maybe you need 3 different "layers" of blocks instead. I hope you understand what I mean by my picture 1_mod.
1. layer: from bottom to beginning of triangle
2. layer: from beginning to end of triangle
3. layer: from end of triangle to top

Some ideas concerning mesh quality:
1. Do you use a inflation layers in your unstructured part? This would be a good idea, otherwise the resolution and accuracy of the boundary layer flow will suffer. If the mesh quality at the leading edge ("fore part") is bad these inaccurate results will be transported downstream and affect the whole blade boundary layer. Please have a look at the first part ("Do use inflation layers"): http://www.simutechgroup.com/CFD/cfd-tips-do-dont.html

2. Maybe you want to improve the skewness of the cells in your structured part. Ideally the grid lines, which run into the blade should hit it with 90°. This is just the case for the first grid line of the structured mesh and the situation seems to get worse downstream the blade. You can improve that by adjusting the node distribution (clustering) along the blade.