Problems with meshing of wind turbine
 

Hey guys,

I am pretty new to Ansys ICEM and I am currently working on meshing a whole horizontal wind turbine (50 m radius) with tower and ground. At the end I want to compare Ansys CFX and OpenFOAM based on this mesh.

My plan is to have at the end a stationary far field domain with the tower and a rotating disk/domain for the rotor.

Up to now I managed to mesh the rotor disk (14 million cells, hex) with a sufficient quality. As the blocking of the rotor is a lot of work, I used the symmetry of the rotor to save some work. So I meshed only one third of the rotor and then copied the geometry and the blocking of one blade.

This worked so far, now I have the problem to include the far field and the tower. To use the symmetry of the rotor I first had to exclude the farfield (not symmetric like rotor) and the tower. Now after having the rotor blocked and I would like to "extend" my blocking to the whole domain, but I am not getting this done correctly. And I dont know if its possible anyway..

So my questions: Is it somehow possible to create the complete meshing in one ICEM project?

I attached some screenshots so that you guys know what I am talking about, the tower is not included yet. The size of the far field is also not final yet.

I would be very grateful if you could help me with my problem!

Thanks a lot in advance!

Regards from Germany,

Bastian

so you did a blocking just for your wind turbine... the only way to expand it is to use the extrude faces... otherwise you should have started with a initial block around the hole geometry them perform splits and use index blocking to ease the works. i can't think of another way to expand you blocking, may be a new blocking of farfield then a merge... i don't think that will work.
I hope i'm wrong, let's see opinions of other member...

hi...
I'm new to icem cfd.I'm doing analysis on an aircraft model as my final year project.I would like someone to help me in meshing the model.Actually when I meshed the model, I'm not able to capture the leading edge properly...Plz help me with this....

yes, I did the blocking only for the turbine as I otherwise would have not been able to use the symmetry of the rotor. Blocking (and meshing) farfield and turbine separately is maybe a better option, I already thought about that. To merge them in ICEM did not work so far.

I think in OpenFOAM there is a possibility to use two different meshes and as far as I know in CFX as well.

As the rotor disk should rotate I anyway need the GGI interfaces right? But I am not sure about the influence of the mesh cell ratio between both sides of the interfaces on the quality of the results. Is there a "rule" for a minimum cell ratio between the rotor disk side and the farfield side of the interfaces?

Thanks a lot for your help!

regards from Germany,

bastian

yes, it's possible to do it in one project. but you've to use sub-topo to stay on top of things. just rmb on topology -> create sub-topo -> select blocks to extract. you can either merge them together later on, or do meshing for each sub-topo and connect them in cfx-pre via ggi.

I prefer to merge the sub-blocking and do the interface in ICEM.....but hey, that's up to you.

you need 3 rot/stat interfaces. inlet, outlet and circumferential direction (as you don't have a casing around your wind turbine :D).

what shape does the tower have?

the biggest benefit of using sub-blocking is, that you have a consistent mesh and no cell size issues @interfaces.

but if it's not possible to get a good mesh (e.g bad cell angles), rather use a ggi or use a hybrid mesh.

I can't give you further advice without any pics of tower shape etc.

hey energy382

Can you give more details about the sub-topo. Where to use and how?

What about making the blocking of your farfield without the turbine, conver to unstructured mesh, and do a conformal merge wih the unstructured mesh of the turbine.
That's the easiest (and fastest) way of doing it I think.

@Broly What about making the hybrid mesh : Hexa in vicinity of blade and tetra in the rest of the domain? Then you may connect the both regions through merge or interface

But I would really be interested in Hexa meshing

Yep it should work as well, but I thought Hexa was the only option for this problem ;)

where is the geometry ?

here.....................


https://dl.dropbox.com/u/68746918/Windturbine.tin

link doesn't work, can you zip it ? make sure its in public folder. thanks a lot

working fine

hey guys,

@ energy382 sorry that I didn't reply on your post but I was on vacation and had some other stuff to do

now I am back on my mesh... for now I meshed farfield and rotordisk separately (hex) and I am now testing GGI connections to connect both meshes. I also worked a bit on your hint with the sub-topology, although it is difficult to use the periodicy of the rotor, this might work. I have to get back to this if my actual concept does not work.

I've done this kind of simulation before (with ICEM hexa). As soon as time permits, I'll give you some suggestions