Learning Forum

[warhammer975]

Hi!

2D task. There is an external stationary cylinder and an internal rotating cylinder (shaft). How to write UDF correctly for pumping a mass of air into the first wall cell near the shaft.

Any suggestions will be very helpful.

Thank you

[Rob]

From the boundary wall look at DEFINE_PROFILE and from a layer (or few) of cells it's DEFINE_SOURCE. For the latter it's generally easier if you have a separate cell zone. 

[warhammer975]

Unfortunately, I'm a complete newbie in this matter. If you don't mind, can you explain this in more detail?

[Rob]

Boundary conditions are used for a surface effect, ie an inlet/outlet/wall and the like. If you need to add (or remove) material from a cell zone (volume effect) then you need a source term. What effect are you trying to replicate? Have you done some/most of the tutorials as those will give you a good idea of how the solver works. 

[warhammer975]

Initially, I wanted the mass flow to be evenly distributed across the entire surface of the inner cylinder (this cylinder must rotate at a given speed) into the gap between the cylinders.

[Rob]

And continues here. 

https://innovationspace.ansys.com/forum/forums/topic/rotating-and-mass-flow-inlet/