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unsteady rotational moving wall (unsteady omega)

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Old   August 29, 2023, 10:34
Default unsteady rotational moving wall (unsteady omega)
youhane kha
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Hi everybody,
I'm new on using udf with ansys fluent and I have a problem with programing a rotating wall as a function of time using UDF. Can any one help me please
I'm working on analysing fluid flow around rotating cylinders in 3D. I already know how to give rotating wall condition and I have already performed simulations for 5 rad/s for example. Now, instead of constant rotational speed, I have to give a time varying rotational speed, i.e., the rotational speed of my cylinder (moving wall) is a function of time.
The problem with ansys fluent is that we can't assign an UDF directly instead of the constant value to the rotational speed, so we must switch to "components motion" and enter the values of x-velocity, y-velocity and z-velocity as UDFs.
Now my question is how these three UDFs must be written to have an equivalent of a rotational speed of this form: Omega = A sin(wt) with a rotation-axis origin of components (a b c) and rotation-axis direction of components (d e f)?
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