We characterize the long-term development of high-viscosity gas–liquid intermittent flows by means of a detrended fluctuation analysis (DFA). To this end, the pressures measured at different locations along an ad hoc experimental flow line are compared. We then analyze the relevant time-series to determine the evolution of the various kinds of intermittent flow patterns associated with the mixtures under consideration. Although no pattern transitions are observed in the presence of high-viscosity mixtures, we show that the dynamical attributes of each kind of intermittence evolves from one point to another within the transport system. The analysis indicates that the loss of a long-range correlation between the pressure responses are due to the discharge processes.

We study a high-viscosity two-phase flow through an analysis of the corresponding pressure signals. In particular, we investigate the flow of a glycerin–air mixture moving through a horizontal pipeline with a U-section installed midway along the pipe. Different combinations of liquid and air mass flow rates are experimentally tested. Then, we examine the moments of the statistical distributions obtained from the resulting pressure time series, in order to highlight the significant dynamical traits of the flow. Finally, we propose a novel correlation with two dimensionless parameters: the Euler number and a mass-flow-rate ratio to predict the pressure gradient in high-viscosity two-phase flow. Distinctive variations of the pressure gradients are observed in each section of the pipeline, which suggest that the local flow dynamics must not be disregarded in favor of global considerations.