flowType for a voxel domain

Dear all,

I would like to build a free surface simulation of a natural area. I produced an STL file which describe the geometry of the domain (bathymetry). I follow a mix of aneurysm and damBreak3d examples.
I have to construct a VoxelizedDomain3D object, but I don’t know which kind of flow type (voxelFlag) I have to give to the constructor in case of a free surface.