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doctsh August 28, 2009 02:35

rotating spring in fluid
i want to study rotating helical spring in low-Reynolds number environment. How to model it in flow3D or any other software. please somebody answer it!!

stefmascio September 1, 2009 10:46

just load your helical spring in .stl format inside the software, and give to it its rotational speed (GMO model, prescribed-fixed axis motion).
But you would need a very thin cell size if the thickness of the spring is small.

doctsh September 2, 2009 01:13

would you please illustrate little?
Thanks a lot for your reply.

As I am a biology teacher, completely new to flow3D and i am learning. Would you please tell me briefly, how to create a very thin helical spring(actually it is bacterial flagella of few nm thickness) in .stl format?

I would be very thankful, if show me steps to do that.

With regards


stefmascio September 2, 2009 08:21

it seems a very interesting application!
To draw your flagella you have to do it in any external CAD software, and then save it as a file with .stl format.
Then with FLOW-3D you can easly import it in the "Meshing&Geometry" tab.
But do you have already done any fluid dynamic analysis (also with other software)? The first time could be quite difficult to get to a good result.

doctsh September 2, 2009 10:12

Dear stefmascio,

thanks again for yout thoughtful reply.
Though I have studied fluiddynamics and physics, i have not used any CFD software. I am struggling with this for long time, but i wanted to solve this using simulation as it is difficult to model in a macroscopic scale.

Do you recommend any other software for this application?
I want the flagella to be rotatated and thrust should be calculated. I want to see the emprical relationship between viscocity, rpm, thrust etc.

I really dont know how to proceed further. This is an important step in my research. without that my four years of research will cometo standstill.
Can you help me to come out of this?

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