Two-phase flow regimes are affected by conduit position, alignment, geometry, flow direction, physical characteristics, and flow rate of each phase as well as the heat flux toward the boundaries. Due to the importance of two-phase flow, numerous regimes have been identified. The first step in studying micro-bubble formation inside a venturi tube is to recognize the type of flow regimes. In this...

The Bubble regime of electron acceleration in ultra-relativistic laser plasma is considered. It has been shown that the bubble can produce ultra-short dense bunches of electrons with quasi-monoenergetic energy spectra. The first experiment in this regime done at LOA has confirmed the peaked electron spectrum (J. Faure, et al., submitted, 2004). The generated electron bunch may have density an o...

Industrial demands for more compact heat exchangers are a motivation to find new technology features. Electrohydrodynamics (EHD) is introduced as a promising phenomenon for heat transfer enhancement mechanisms. Similar to any new technology, EHD has not been understood completely yet and requires more fundamental studies. In boiling phase change phenomena, nucleation is the dominant mechanism i...

We analyze the properties of naturally formed nanobubbles in Lennard-Jones molecular dynamics simulations of liquid-to-vapor nucleation in the boiling and the cavitation regimes. The large computational volumes provide a realistic environment at unchanging average temperature and liquid pressure, which allows us to accurately measure properties of bubbles from their inception as stable, critica...

The Subprime Bubble preceding the Subprime Crisis of 2008 was fueled by risky lending practices, manifesting in the form of a large abrupt increase in the proportion of subprime mortgages issued in the US. This event also coincided with critical slowing down signals associated with instability, which served as evidence of a regime shift or phase transition in the US housing market. Here, we sho...

The purpose of this study is to investigate and identify the periods of formation and bursting of speculative bubbles in Iran's capital market by creating a state space model and two-mode switching regime (mode 1 is bubble growth and burst stage and mode 2 is the time of bubble loss) during the period from April 2011 to March 2018. The Oxmetrics 7 software is used to investigate the existence o...

in this paper, direct numerical simulation of two-phase incompressible gas-liquid flow for simulation of bubble motion in a microtube is presented. microtube radius is 10 µm. the interface is tracked using volume of fluid (vof) method with continuous surface force (csf) model. the flow is solved using a finite volume scheme, based on piso algorithm. numerical simulation is performed on a axisym...

The quasi-steady migration and deformation of bubbles rising in a wall-bounded linear shear flow are investigated experimentally in the low-but-finite-Reynolds-number regime. A travelling optical device that follows the bubble is used for this purpose. This apparatus allows us to determine accurately the bubble radius, contour and rising speed, together with the distance between the bubble and ...

Bubble formation at two, three, four and six symmetrical ori&ces has been investigated by high-speed photography and analysis of chamber pressure 6uctuations. Regimes of synchronous, alternative and unsteady bubbling were clearly identi&ed, and the e7ects of ori&ce spacing and liquid depth on bubbling synchronicity and frequency were studied. Theoretical predictions of bubble frequency and aver...

We investigate experimentally the behavior of liquid foams pumped at a given flow rate through a single pore, in the situation where the pore diameter is smaller than the bubble diameter. Results reveal that foam invasion can be observed only within a restricted range of values for the dimensionless flow rate and the foam liquid fraction. Within this foam invasion regime, the liquid content of ...