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M a h d i August 24, 2009 20:25

Hex mesh
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Dear all:

Does anyone know how to Hex mesh a cylinder with 25 oval shape holes in side wall which are covered by small surfaces?

The geometry is a uniflow 2-stroke engine cylinder wich I covered the inlet ports by faces in order to divide the volumes as I need the in-cylinder volume separately for dynamic mesh. I have attached a picture of the geometry in gambit. I almost followed all the trickes in the tutorials but none could solve the issue .


M a h d i August 25, 2009 10:34

Please help! I am really stucked with this issue.

How to hex mesh a cylinder with holes that are covered by small caps which are part of the main cylinder?

meon August 26, 2009 02:16

2 Stroke Engine Hex mesh
This is a tricky one all right but you are lucky in a way because there are 25 inlets and not 23.
The solution is to divide the 25 by 5 and create a central 5 pattern. Then loop the inlet ports into themselves.

The ports are round at the top but not completely from your CAD image. I'd just square these off because you are going to be using a sliding arbitrary interface across the ports any way.

Let me know if you stuck and need any more help finishing the full model.
For instance if you need the round port detail.
By the way, in case you are wondering I built this will a new Hex meshing program called cheetahSTC from
Only took 10 minutes.


M a h d i August 26, 2009 11:51

Dear Meon:

Thanks for your lovely trick. But the thing is that I am using Gambit 2.3.16. and that's a must for me to mesh the geometry by that. However I like that program, but maybe later.

Now, the question is that can I mate a simple cylinder wall with no holes with a small surfaces in which cover the ports in order to take advantages of Interface command in Fluent? Does it work in my case?

In this way, I have to surface that connected together and are not perpendicular to each other and seems to be suitable for interface command in fluent. Also, The cylinder mesh will be very nice as well as ports mesh since the geometry is not that complicated.

Does any one confirm this idea?


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