Mesh generation
 

Hi everybody!
I'd like to ask for help in ICEM CFD.
I've just started my PhD and began to build mesh for calculation.
I am trying to simulate a 3D hydrogen release and jet-fire in an enclosure in Fluent, but first I need to build mesh in ICEM CFD 13.
The geometry is the cube enclosure 1x1x1m3 with wall thickness 0.02m, which is in the centre of the outside environment of hemispherical shape. In the centre of this cube there is an inlet pipe for release. On the side wall of the cube there is a vent opening which is near the ceiling.
I’ll try to describe the problem which I faced.
First I did all tutorials, but still no idea of how to block that geometry such that in different places I’ll have the exact mesh size.
There are four zones with different sizes: pipe, vent opening, walls of the cube, space inside of the hemisphere.
Each of them should be differing in mesh finest.
I have to built hexahedral mesh which will increase its size from pipe to cube wall, in wall should be another mesh size for heat transfer, as well as vent opening with more finest mesh inside, mesh for the hemisphere should have the biggest size.
Geometry is attached.
Could you tell me please where can I find relevant information on how to do this?
I will really appreciate your help.

try sphere cube tutorial included in ICEM Help. You can also look at the video tutorial.


http://www.youtube.com/watch?v=DRbkSO0igT4&feature=plcp

http://www.youtube.com/watch?v=5vAKVVDF_P8&feature=plcp

http://www.youtube.com/watch?v=dHfAe_6weZE&feature=plcp

Hi everyone! Thanks for the previous answers!
I recently addressed to you with problem of mesh generation.
Now I faced another one - too many cells and too fine mesh in region which is not related to specifics of the modeling.
The task is to investigate hydrogen release dispersion and fire inside of cubic enclosure 1x1x1 m3, as well as heat transfer though the walls.
I built hexahedral block structured mesh and found there are too many cells in the whole region.
In attachments there are pictures of my mesh central plane in which it showed where I need to have more course mesh.
The question is how having block structured mesh in the whole domain do built tetrahedral or mixed mesh outside the cube, is there any tools how to pave the mesh inside the cube to get less amount of cells? At the moment I have more than 2 million, I need less than 1 million.
Can I refine specified zones of my domain? To grid them more fine or more course? Can I have block structured and block unstructured mesh at the same time time and in the same domain? In attachments you will find approximate mesh what I want to archive.
I will be much appreciating any help!
Thank you!