Can you give me some advise to build in/outflow boundary conditions?

[qwerty12345697]

I want to achieve the same condition as the paper(Simulation of Soil Fluidization Around a Pressurized Leaking Pipe Using the Material Point Method). Can you give me some advise to build in/outflow boundary conditions?

[murphy-john]

https://www.sciencedirect.com/science/article/abs/pii/S004579301830728X?casa_token=utTlVIWUXIYAAAAA:tFbLXMjyu8XMSdL7bkfxE2lkW6ys4e5oE5wgc_DuTznAkrEzlp9VwztsErg9ezh4fEPaYRECHlQ

[FrancescaCeccato]

You can probaly check this discussion: #174