In structured hexa mesh case, What is the best grid generation software ?

My vote goes to ICEM Hexa - very robust and flexible, a bit tough to get started with though.

I will also suggest to go for ICEM Hexa

It depends on what you want to mesh. ICEM Hexa is very good in some aspects, but less good in others. Not so good when it comes to meshing thin regions or when you want to modify a single node. No problem even with tough topologies though, handles connectivity automatically since it forces you to work that part of the problem out first. But, for some turbomachinery problems I would not use hexa. For example, it has difficulties with end gap leakage for blades in a compressor or turbine. And some time back I also meshed something that resembled a pump manifold, but slightly more complicated, and ran into some problems with topology. When the number of coordinate axes (three for each block in hexa) got large, hexa had trouble splitting or forming new blocks.

But in spite these small problems I would still say that hexa is the best all round mesher out there. Usually very high price though. Some commercial codes come with a mesher though. Fluent comes with Gambit which can generate hex mesh, and CFX also comes with a mesher (only tet, I think). So you might be ok with these at no extra cost.

Good luck,,

Martin

Compared to the mesh quality you can obtain using GridPro , Icem HEXA if far away from beeing good in this point.

An advantage of HEXA might be, that it does not depend very much on the quality of the geomety description.

Also the topology creation within HEXA is a bit unflexible, especially if you want to change some parts of the topology or put several things together or if you want to create some parts of the topology manually ...

thanks all. I know ICEM have elliptic solver. but it's not easy to handle. Is there any Information about that ? (In Multi-block structured grid, I want to solve block-interface freely ~)

There is now an example of a scroll mesh (nastran format) created with Gridpro on

http://www.beilke-cfd.de/scroll_gridpro.nas.gz

Didn't see STAR-CD's POLYhedral mesher (pro-am), mentioned in the above. It can deal with more than just HEX. Thought you should consider this too - comes either standalone or with STAR-CD.

You might want to take a look at Gridgen. It's been used for structured hex grid generation since 1984, has a very broad and deep suite of tools for getting a very high quality grid. Gridgen is used quite heavily in the aerospace industry, where highly accurate CFD solutions are critical. In addition to grid quality, Gridgen's easier to learn and use than other products. To learn more take a look at www.pointwise.com.