Abstract: A method of moving materials comprises: flowing a first fluid in an axial direction, the first fluid characterized by inertial forces dominating viscous forces of the first fluid; flowing a second fluid in the axial direction, the first and second fluids miscible with one another and the first and second fluids having an interface region therebetween; permitting a reaction to create a reaction product in the interface region, the reaction product mitigating flow-disrupting mixing between the first and second fluids.