WordNet sense 1 (the motion characteristic of fluids (liquids or gases)):

flow

WordNet sense 2 (designed or arranged to offer the least resistant to fluid flow):

aerodynamic, sleek, streamlined

WordNet sense 3 (having a surface free from roughness or bumps or ridges or irregularities):

smooth

WordNet sense 4 (moving smoothly and continuously):

streaming

WordNet sense 5 (in motion):

moving

WordNet sense 6 ((of water) rising to the surface under internal hydrostatic pressure):

artesian