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bramdiff September 24, 2010 09:12

Advice on vertical axis turbine modelling
Dear all

I have just started my PhD and need to model a vertical axis turbine. I am new to cfd and would like your advice.

I need to model the turbine flaps opening and closing, they open/close depending on the fluid flow, and are not motor driven. Their movement is restricted to 180 degrees.

My problem is a bit like trying to model the wind blowing a door open, and if the wind was coming from the other direction, it would blow the door shut. my question is how would you model this? is it a fsi problem? or do I have to predict the position of the flaps (not desirable)? I have been told that I would need to write a udf to calculate the movement based on the pressure difference either side of the flap- is this a recommended way of solving this?

I have been advised that either fluent or cfx have this capability, which software do you think is more appropriate? also would i need the icem meshing software as the flaps can move 180 degrees, or would the built in meshing tools be able to handle this?

Any ideas/suggestions are extremely helpful as I am trying to gather as much infomation as possible at the moment.

Many thanks in advance


ghorrocks September 25, 2010 19:30

FSI is required when the bodies deform. I think what you describe does not deform, but are rigid bodies which move. In this case you are looking for the rigid body solver. I recommend you look at the preview version of CFX V13. It has lots of new stuff for the 6-DOF solver to do fluid/rigid body interaction. You can do it in CFX V12 but you will need to use beta features and it is not as developed.

bramdiff September 27, 2010 10:48

Hi Glenn

Thanks for your reply,

the rigid body solver is the sort of thing I am looking for, do you know how long it will be untill cfx13 is released, or is it out now and im just being stupid and cant read their website properly?

Do you or does anyone have any experience in flow-3d? they seem to be able to solve my problem with the General Moving Object solver, does anyone know much about this compared to using cfx, as I currently dont know which software to go for, and I obviously want the best one for my research?

Again thanks for your help,


ghorrocks September 27, 2010 19:11

CFX V13 has not yet been released. Talk to CFX support about getting a preview version.

I have used Flow3D but not the general moving object solver. Your best bet is to run a demo example in both software and see which one does it best.

bramdiff September 28, 2010 04:27

Many thanks, i am in contact with both companies at the moment.

i'll let you know how I get on...


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