[andrew97]

Hi, I'm new to the entire concept of UDFs and was wondering if there were any good materials out there on how to define them, particularly ones involving rotating rigid bodies around an axis and where the speed of rotation is linked to the flow i.e. lift produced by the body?

I hope that makes sense, thanks.

[obscureed]

Oof! Have a look at Dynamic Mesh, and in particular "Six DOF". This might involve UDFs in the end, but hopefully very simple ones (like, 4 lines long) if at all. It does not sound easy, though.

[andrew97]

Originally Posted by obscureed

Oof! Have a look at Dynamic Mesh, and in particular "Six DOF". This might involve UDFs in the end, but hopefully very simple ones (like, 4 lines long) if at all. It does not sound easy, though.

I managed to figure it out using that method, i think, didn't even need the UDF. Thanks.

Though on a UDF sidenote, do you know how to vary inlet velocity using a UDF?

[obscureed]

For the benefit of posterity, please could you sketch out the method you used for the rotation?

On the sidenote: for varying inlet velocity (as a function of time, position, etc), see DEFINE_PROFILE in the Fluent Customization Manual.

[andrew97]

Originally Posted by obscureed

For the benefit of posterity, please could you sketch out the method you used for the rotation?

On the sidenote: for varying inlet velocity (as a function of time, position, etc), see DEFINE_PROFILE in the Fluent Customization Manual.

It seems like I was incorrect and I can't recreate what the results I got earlier.

Thanks for the help

Edit: Nope, wrong again haha. If you follow Raef Kobeissi's 6DOF turbine tutorial you'll be fine. I just overestimated the moment of inertia for my blades and so it couldn't turn.