[Bdew8556]

Hey guys,

Standard post here, UDF help. No idea where to start.

I'm using Fluent

I've got a model where I'm calculating the velocity through a slice in the domain, that's a report def called "slice velocity"

The outlet to my model is a mass flow rate outlet.

What I would like to do is adjust the mass flow rate outlet after every iteration to target a specific slice velocity.

Any ideas??

[thedal]

If I understood correctly, you are changing your outlet boundary condition specifications after every iteration based on a value?

Try creating DEFINE_PROFILE() may be, and change the boundary condition (massflow rate in your case) and calculate the value based on the slice velocity?

[AlexanderZ]

that is not that trivial task
depends on the difference in geometry of slice and outlet approaches could be different

in case you need average value from slice -> its relatively easier
I don't member exactly, but you may try to make and interior instead of slice, than you would be able to get data from that interior inside UDF

to make an interior you need to split your mash in advance -> you would have 2 zones with same material and a boundary between them with type interior

other option is to write profile of report def called "slice velocity" and attach it to the outlet
you would need TUI script to do that (and it would work smoothly only in case your slice has the same geometry with outlet)

[Bdew8556]

Thanks guys,

yep looking to change every iteration.

I'm super new to UDFs so I'm completely in the dark, any examples?

I suppose I'm trying to "target" a velocity through the "slice" which is through an internal part of the domain, in this case the area around cooling fins in an electric motor. There is an outlet downstream that I'm setting as mass flow rate.

Any help much loved.