Hello to everybody:

I would like to solve the NSE (Navier Stokes Equations) in 3D and with PBC (Periodic Boundary Conditions). I am working with a cube whose dimension is (2pi*2pi*2pi). I know that I must put PBC among nodes that belong to opposite boundaries, but my question is: (1) Must I put PBC over my three components of velocity (u,v,w) in each boundary? (2) Must I put PBC over PPE (Pressure Poisson Equation) also?

Thank-you very much in advance and best regards! Isa

Periodic BC is a very man made stuff. It assumes the solution will be periodic although in reality the nature or the god never tells that.

once you assume periodic, very stuff is periodic. and the flow field is a very nice well-posed system.

implementation of periodic is very easy. it's a node-counting business.