Correcting mistaken brace in assemblePBC() before the periodic modification of the inverse matrices. This didn't affect the previous result because without gravity and beta, the inverse matrices make no effect. When turning on gravity, the periodic walls are contamined in the crossflow. No idea if because the splitting of forces.
MountPeriodicVectorsNew() was being called instead of MountPeriodicVectors() after the remeshing operations. Possibly also working because there wasn't change of node indexing.
Adding initPastCylinderFlow and updating main.