Hello,
I am not sure to have the latest version of the SPE11 benchmark description but I find the following description confusing:
p19, it is written that " we introduce additional volume at the horizontal boundaries" and then (at the specification of the boundary volumes per area) this volume is zero at the top and bottom boundary (which are the horizontale boundaries) and non-zero at some parts of the vertical boundaries.
It can be misleading.
Best,
Laurence Beaude