Achieving periodicity when flow exits the domain minimum
Since the DualSPHysics team was kind enough to help me resolve an issue I was having with periodic boundary conditions, I'm sharing the solution here so that others may benefit.
I have been coupling DualSPHysics to other solvers, and in some cases the other solvers favor setups in which the flow exits at the minimum end of the domain (for instance, at x=0). To make the flow be reintroduced at the other end of the domain (for instance, at x=10) requires a slight adjustment of XPeriodicIncZ in your case XML.
Let's say that you want the flow to increase z by 2 meters. Instead of "XPeriodicIncZ = 2," simply add a negative sign: "XPeriodicIncZ = -2." The same goes for a lateral shift in the y-direction. If the flow exits the domain minimum and is to be reintroduced at the domain maximum with a positive shift in z of 2 and a negative shift of y of 3, then "XPeriodicIncZ = -2" and "XPeriodicIncY = 3" will do the trick.
TLDR: Reverse the signs of your _PeriodicInc_ values when your flow exits the minimum end of the domain and is reintroduced at the maximum end of the domain.
I have been coupling DualSPHysics to other solvers, and in some cases the other solvers favor setups in which the flow exits at the minimum end of the domain (for instance, at x=0). To make the flow be reintroduced at the other end of the domain (for instance, at x=10) requires a slight adjustment of XPeriodicIncZ in your case XML.
Let's say that you want the flow to increase z by 2 meters. Instead of "XPeriodicIncZ = 2," simply add a negative sign: "XPeriodicIncZ = -2." The same goes for a lateral shift in the y-direction. If the flow exits the domain minimum and is to be reintroduced at the domain maximum with a positive shift in z of 2 and a negative shift of y of 3, then "XPeriodicIncZ = -2" and "XPeriodicIncY = 3" will do the trick.
TLDR: Reverse the signs of your _PeriodicInc_ values when your flow exits the minimum end of the domain and is reintroduced at the maximum end of the domain.