Meshing on a Complicated Geometry
 

I need to make a good mesh on a very complicated geometry (see pictures). I plan on running an LES simulation on a model of the human upper airways (lungs). in the form of an STL I have used Materialize software to extract a geometry from CT scans . I have access to ICEM and I wanted to ask where to begin on a model like this? My thoughts were to use a tetrahedral mesh because of complexity. It would be great if I could use hexahedral and still get good quality elements because of the reduction in computational time. I think it would be good to use prism layers at the surface but I am not sure if that would cause a problem with LES. Either way it is important to have very small elements near the wall. I do not have a lot of experience with meshing and I wanted to know if anyone had any thoughts or suggestions for me. What kind of meshing strategy would you use for a geometry like this?

Thank you for your time,
Timothy


http://web.mst.edu/%7Etav98f/Wext1.png
http://web.mst.edu/%7Etav98f/Wext2.png

Simon has suggested a method of blocking for this geometry that I have tried with some results.

I have started with a bounding block. I split the block in half from top to bottom at the first split in my geometry. Then, because the splits in my geometry were not very sharp, I split the lower block into three blocks and deleted the middle block. I moved the nodes of the blocks so that the two lower blocks aligned with the two split directions. I would then perform a similar procedure on the next split on each side of the first split. I continued this process associating as much as possible along the way until my entire geometry was blocked.

Next Challenge
 

The result looked pretty cool but has some overlapping elements. (see picture)
http://web.mst.edu/~tav98f/overlap.jpg
Below is my blocking structure in that region.
http://web.mst.edu/~tav98f/blockstr.jpg

Does anyone know why I may be getting overlapping mesh here?

I do not know what the problem is so I do not know the information one would need to figure out what is wrong. If you need any more pictures or information let me know.

Thanks,
Timothy