The growth and breakdown of localised disturbances into a turbulent spot in a Mach 2 boundary-layer flow have been investigated by direct numerical simulation. In particular, the interaction of a turbulent spot with a shock-induced separation bubble is studied. The primary vortex structures triggered by the injected low momentum fluid and the metamorphosis of the hairpin structures into a turbu...

As widespread, continuous instrumental Earth surface air temperature records are available only for the last hundred fifty years, indirect reconstructions of past temperatures are obtained by analyzing "proxies". Fluid inclusions (FIs) present in virtually all rock minerals including exogenous rocks are routinely used to constrain formation temperature of crystals. The method relies on the pres...

In this research, hydrodynamics of the Bubble Train Flows (BTF) in circular capillaries has been investigated by Direct Numerical Simulation (DNS).The Volume of Fluid Based (VOF) interface tracking method and streamwise direction periodic boundary conditions has been applied. The results show that there exists an appropriate agreement between DNS and experimental correlation results. The re...

Oxygen gas-liquid mass transfer coefficient was measured in a gas-induced pulsating flow bubble column. Pulsating amplitude had a great influence on kla under pulsating state of equal base flow and pulsating flow, which was enhanced up to 30 % compared with that under steady state; however, it had a negative effect on mass transfer under a fixed low base flow. It was also found that kla had a n...

This work developes an approach for numerical simulation of fluid flow through a domain with a complex geometry. We consider a finite element discretization of Stokes-Brinkman equation for modelling the incompressible viscous flow inside a fluid-solid systems combined with Lagrange multiplier/fictitious domain and special spherical bubble functions. Well-posedness of the new method, á priori es...

The effect of surface tension on the Rayleigh-Taylor (RT) instability and Richtmyer – Meshkov (RM) instability induced development of nonlinear structures like spike and bubble at two fluid interface have been investigated .In case of RT instability, the surface tension reduces the velocity of the tip of both the bubble and the spike by the factor (1-k /3 kc ) where, kc =(h-l)g/T .For k > 3 k...

The methodology combining Axisymmetric Drop Shape Analysis (ADSA) with a captive bubble (ADSA-CB) facilitates pulmonary surfactant related studies. The accuracy of ADSA-CB is crucially dependent on the quality of the bubble profile extracted from the raw image. In a previous paper, an image analysis scheme featuring a Canny edge detector and a Axisymmetric Liquid Fluid Interfaces-Smoothing (ALF...

Over the last half of the twentieth century, a number of purely empirical and mechanismbased correlations have been developed for pool nucleate boiling. Empirical correlations differ from each other substantially with respect to the functional dependence of heat flux on fluid and surface properties, including gravity. The mechanism-based correlations require knowledge of the number density of a...

In this paper, a modified two-fluid model has been adopted to simulate the process of upward vertical subcooled flow boiling of refrigerant R-113 in a vertical annular channel at low pressure. The modified model considers temperature dependent properties and saturation temperature variation and was validated against a number of published low-pressure subcooled boiling experiments. The results s...

A Lagrangian-Eulerian numerical scheme for the investigation of bubble motion in turbulent flow is developed. The flow is analyzed in the Eulerian reference frame while the bubble motion is simulated in the Lagrangian one. Finite volume scheme is used, and SIMPLEC algorithm is utilized for the pressure and velocity linkage. The Reynolds stresses are modeled by the RSTM model of Launder. Upwind ...