[bmaldi]

Hello everyones,

Finally i could make the simulation for my ducted propeller,
but i have other problems,
In my results of streamlines, the water was rotating in nozzle only,
and i still confuse about the function of interfaces region,
in this thread, i attached the figures of ducted result, blades result, and the motion input,
because in the simulation, i couldn't modify my motions specification being rotation, and how to solve it?

need help.

[me3840]

You likely can't modify the motion because you have a steady-state simulation prepared. Motion only applies to transient cases.

What confuses you about the interfaces?

[bmaldi]

Originally Posted by me3840

You likely can't modify the motion because you have a steady-state simulation prepared. Motion only applies to transient cases.

What confuses you about the interfaces?

yes, that why i couldn't modify and my streamline looks wrong,
i am confusing about interface, how to know the right size for our interface,
for example, my diameter propeller 130mm. and how if we don't use interface? is it problem for the result?

[me3840]

Well, you are plotting streamlines of velocity in a rotating frame, that's probably why they look wrong. If you are in a rotating frame you need to view either relative velocity or velocity relative to the given frame.

I don't understand your interface question still. What do you mean the size of the interface? Do you mean 'how far away should the interface be from my geometry of interest?'

If so, in general it should be relatively far, enough so the important flow structures are carried in the interface for MRF. If you are doing RBM, the location of the interface is arbitrary, although is beneficial for it to be not massive, as rotating a lot of cells is costly.