[zhangdongjie]

I'm simulating a nozzle with rarefied gas. Its kn number is very large. First order slip and temperature jump must be added. I use Maxwell slip equation to write UDF, but I don't know where UDF should be loaded. I look up the data. The sliding speed can be loaded into the shear stress, so where is the temperature jump loaded? Is it loaded directly into the wall temperature? But my wall temperature is fixed at 300K. If anyone has a compiled UDF file, can you send me one? Thank you very much.1248385182@qq.com

[pakk]

I hope you are aware of the low-pressure boundary slip option in Fluent. If not, look it up in the manual, it will simplify your problem a lot.

[zhangdongjie]

Originally Posted by pakk

I hope you are aware of the low-pressure boundary slip option in Fluent. If not, look it up in the manual, it will simplify your problem a lot.

Thank you very much for your reply. I watched the low pressure boundary slip, which helped me a lot. But it seems that fluent 2D doesn't have the low-pressure boundary slip button, only 3D does. What should I do. In addition, if I use the low-pressure boundary slip to calculate, is it different from UDF?

[pakk]

Originally Posted by zhangdongjie

, if I use the low-pressure boundary slip to calculate, is it different from UDF?

A UDF is something that you program. You tell the UDF what yo do. So if you want the UDF to be different, it can be different. If you want it to be the same, it can be the same (with some work).