title: Imaging the velocity profiles in tubeless siphon flow by NMR microscopy.
abstract: We report on the use of NMR micro-imaging to observe flow within a tubeless siphon. The flow is maintained in a visco-elastic liquid of high extensional viscosity, namely 0.5% w/v 8 million Dalton polyethylene oxide in water. The velocity profiles reveal a significant velocity gradient in the vertical direction as well as a transition from near-Poiseuille flow at the pipe entrance to plug flow far from the pipe entrance towards the base of the tubeless siphon.
mesh_terms: D005240:Feasibility Studies; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D009038:Motion; D011092:Polyethylene Glycols; D012212:Rheology / Q000295:instrumentation / Q000379:methods*; D012996:Solutions; D012997:Solvents; D014783:Viscosity; D014867:Water
chemical_list: D012996:Solutions; D012997:Solvents; D014867:Water; D011092:Polyethylene Glycols