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UDF to make a flap move

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Old   October 8, 2010, 06:03
Default UDF to make a flap move
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Dear all

I am new to fluent, and am currently learning the tutorials etc, and have a question regarding how exactly a udf works, and how i could use them. As part of my phd research, i am working on a vertical axis turbine, but the fluid is allowed to move the flaps (or blades) i.e consider it a rigid plate that is pin jointed at one end. Depending on the position of the flap the fluid will hit it, and rotate it, and this is what i need to model. (also analogous to model a door being blown by the wind I want to know how much it would move)

Many people have advised me that a udf is needed, the pressure on either side of the flap can be calculated and thus a resultant force. this can be then linked to a rotation on the flap.

this is great but I still have a couple of questions...

in terms of relating the movement would you use simply the relationship of centripetal force to angular velocity, ie F=m*r*Omega^2??? if this was the case would the udf calculate the resultant force, and return the angular velocity of the flap, would fluent then automatically give the flap this angular velocity and therefore move it?

also does a udf perform its calculation once every timestep, or for every iteration, or can you set that??

If someone could breifly explain what fluent does, and if you think the above solution strategy is valid/invalid, please feel free to comment

If anyone has any other suggestions or ideas of how this can be done im all ears, your help is appreciated!!

Many thanks

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