This paper reports on an experimental study characterizing the laminar-turbulent transition for water flow in circular microtubes. Microtubes with diameters in the range 16.6–32.2 lm of varying length were employed over the Reynolds number range 300–3400. The volume flowrate was measured for an imposed pressure differential using a timed displacement technique. Additionally, the viscous heating...

The renormalization group (RNG) analysis of the Kosterlitz–Thouless (KT) phase transition is a basic paradigm in statistical physics and a well-known success of the RNG approach. It was recently shown that the derivation of the RNG parameter flow for the KT problem rests on the assumption of one-sided polarization, which is implausible and cannot be derived from first principles. We extend this...

Abstract. Three-dimensional transonic flow over a delta wing is investigated using several turbulence models. The performance of linear eddy viscosity models and an explicit algebraic stress model is assessed at the start of vortex flow, and the results compared with experimental data. To assess the effect of transition location, computations that either fix transition aft of the leading edge o...

Turbulent flow of liquid sodium is driven toward the transition to self-generating magnetic fields. The approach toward the transition is monitored with decay measurements of pulsed magnetic fields. These measurements show significant fluctuations due to the underlying turbulent fluid flow field. This paper presents experimental characterizations of the fluctuations in the decay rates and induc...

The cellular automaton model for traffic flow exhibits a jamming transition from a free-flow phase to a congested phase. In the deterministic case this transition corresponds to a critical point with diverging correlation length. We present data from numerical simulations which suggest the absence of critical behavior in the presence of noise. The transition of the deterministic case is smeared...

Plane Couette flow and pressure-driven pipe flow are two examples of flows where turbulence sets in while the laminar profile is still linearly stable. Experiments and numerical studies have shown that the transition has features compatible with the formation of a strange saddle rather than an attractor. In particular, the transition depends sensitively on initial conditions and the turbulent s...

Material flow analysis (MFA) describes a class of methods that allow analysing and designing material and energy flow systems like supply chains, eco-industrial parks or production sites. Material flow networks are one of the methods in the field of MFA. Based on the Petri nets, the material flow network make it possible to conduct static MFA (steady-state modelling) as well as dynamic MFA (con...

Flow characteristics of water were tested in a rectangular microchannel for Reynolds number (Re) between 0 and 446 by terahertz time domain spectroscopy (THz-TDS). Output THz peak trough intensities and the calculated absorbances of the flow were analyzed theoretically. The results show a rapid change for Re < 250 and a slow change as Re increases, which is caused by the early transition from l...

The stepped channel design have been used since more than 3,000 years. It is understood that low flows behave as successions of free-jets (i.e. nappe flow) while large discharges skim over the pseudo-bottom formed by the step edges. For a range of intermediate flow rates, a transition flow regime takes place. The dominant feature is stagnation on the horizontal step face associated with signifi...