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-   -   Free surface problem: hull mesh questions (http://www.cfd-online.com/Forums/openfoam/83100-free-surface-problem-hull-mesh-questions.html)

albertofast December 14, 2010 13:20

Free surface problem: hull mesh questions
 
Hello!
I'm trying to evaluate the wave pattern generated by a sailing boat hull at Fr=0.35.
After a quite long period studying an analogue problem with the wigley hull reported in this forum and after getting a little more experienced i would try with my model: it's a sailing boat of 12 meters.
Let's start from the beginning: i'm trying to mesh it in a very similar way to that used for the wigley hull (posted in this forum) but as the geometry is a little more complicated i'm still working on it.
I'm also trying to understand wich is a good preprocessing software to get the final mesh and boundary conditions for openfoam.
As this is an initial study, hull appendages can be removed.
As you can see i have a lot of work in front of me so any sugestion is welcome, thank you very much.

I generated to hull geometry by myself and there is no commercial interest in this post. You can use theese files as you want...just let me know if you get the solution!
http://dl.dropbox.com/u/14793999/hull.zip

colinB December 15, 2010 03:50

Hi Edoardo,

You are not the only one working on problems like this.
I'm working on this for the last four month now, not only meshing,
but also resistance calculations, generating of wave patterns and so on.

As I can see from your zip file is that you have iges files already which is
actually a good starting point, I use the same.

For me the best suiting OpenSource software to get from these kind files to
a proper mesh is using
Salome and the OpenFoam included meshing tools blockMesh and
snappyHexMesh.

With Salome you create a solid of your geometry and store it as a hull.stl
file.
This you copy in your case directory in the
constant/triSurface folder.

Then you create a simple block or if you prefere a wedge background
domain with all necessary BCs
Once you have done that you include your stl file in the
snappyHexMeshDict file and adjust your mesh to your needs.

After that simply execute
blockMesh
snappyHexMesh -overwrite

and you are done.

But be carefull: snappyHexMesh is as hard to learn as OpenFoam and I
highly recommend you the motorBike tutorial in the simpleFoam tutorials
and to read the docmentation section in the user guide of OF.

For my needs this system is sufficient, however I have no experience in
using engrid or other meshing tools which might also be good to mesh a
ship hull form.

For more specific questions on salome and sHM you can use the specific
forums in the OpenFoam meshing section.

regards
Colin

sail December 15, 2010 20:50

hi Alberto.

first of all good luck for your work. from what friends of mine have said doing those analysis with OF you'll need it.

^__^

on the other hand, i have a question for you. do you have any experimental data about this hull?

i'm afraid i can't help you for the analysis setup, since i'm a true beginner of OF, but i'll try to mesh it for you using commercial software. just do not hold your breath, because it can take me some time.

bye


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