Simple Siphons, a Model System for the Study of Nonequilibrium Processes

Simple reentrant tube siphons are amongst the simplest and experimentally most easily employed fluidics devices having the potential to be a model system, supporting common platform investigations of nonequilibrium processes, and nonequilibrium phase transitions in the form of laminar to turbulent flow transitions.  Nevertheless, the underlying physics required to predict the flow and transition performance of these simple devices remains poorly understood today and a subject of debate.  We report on our study of some 40 siphon tubes having diameters ranging from 0.16 to 1.27 cm, lengths of 3.0 to 30 m, and being operated at temperatures ranging from 10 to 30 C.  The objectives of the study are two-fold, 1) to improve the understanding of the underlying physics and predictability of reentrant siphon tube performance, and 2) to measure and characterize the transition to turbulence in the 200 to 20,000 Reynolds number regime.  The focus of this talk will be on our finds regarding the self-similar performance characteristics of simple tube siphons.