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-   -   How to create rotating flow???? (https://www.cfd-online.com/Forums/main/69833-how-create-rotating-flow.html)

TAS November 6, 2009 01:52

How to create rotating flow????
 
Hey all,

This is my first post and it is out of some desperation...

I have been trying to create a working CFD simulation for the following case. I have a Helical Aerofoil (spiral) and I need to perform a CFD analysis on it.
The case i need to setup is as if the aerofoil is rotating at a high tangential velocity, as well as moving forward. To help you imagine what I am talking about...Look at this...

http://en.wikipedia.org/wiki/File:Ecoli_flagellum.jpg

I attempted to create a Cylidrical Control Volume, with walls set as Symmetry, an Outflow and a Velocity Inlet. I set the velocity inlet to apply an Axial Velocity and a rotational speed. The issue is, at the edge of the control volume I get the flow rotating correctly and moving in the right direction, however through the centre of the cylinder I have a helical flow reversal, where the Axial velocity is moving the wrong way.

As far as it being a suitable control volume for the analysis, it isnt. Does anyone have any ideas as to what kind of Mesh, Boundary Conditions and anything I need to successfully Model the flagellum...?

Someone mentioned to me to use a dynamic mesh that rotates, however I have no idea how to use it...


Any help will be great.

Thanks
TAS

PS: I am using GAMBIT and FLUENT (and i have already overcome the geometry import issues with GAMBIT)


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