To jump out of water onto sea ice, emperor penguins must achieve sufficient underwater speed to overcome the influence of gravity when they leave the water. The relevant combination of density and kinematic viscosity of air is much lower than for water. Injection of air into boundary layers (‘air lubrication’) has been used by engineers to speed movement of vehicles (ships, torpedoes) through s...

gas-lift pumps are devices for lifting liquid phase incorporating the gas phase to be injected in the bottom of liquid column. they are widely used in various industrial applications such as oil extracting in petroleum industries. gas-liquid flow being the main part of the flow through these systems, flowing in vertical pipes of gas-lift pumps has different regimes namely bubbly, slug, churn an...

Over the past few decades, high-performance heat-transfer devices have been studied for numerous applications. Boiling flow in such confined spaces induces high-frequency instabilities that directly influence performances. A small-scale water vaporizer with 10 mm-sized channels is experimentally over a wide range of vapor quality (0.05–1). The peculiarity setup transparent window allows high sp...

The effects of unsteady bubble dynamics on cavitating flow through a converging-diverging nozzle are investigated numerically. A continuum model that couples the Rayleigh–Plesset equation with the continuity and momentum equations is used to formulate unsteady, quasi-one-dimensional partial differential equations. Flow regimes studied include those where steady-state solutions exist, and those ...

The bubbles involved in sonochemistry and other applications of cavitation oscillate inertially. A correct estimation of the wave attenuation in such bubbly media requires a realistic estimation of the power dissipated by the oscillation of each bubble, by thermal diffusion in the gas and viscous friction in the liquid. Both quantities and calculated numerically for a single inertial bubble dri...

It is well known that processes of first order phase transitions may have occurred in the inflationary era. If one or more occurred well before the end of inflation, the nucleated bubbles are stretched to large scales and the primordial power spectrum contains a scale dependent non-Gaussian component provided by the remnants of the bubbles. We predict the anisotropies in the cosmic microwave ba...

A set of two phase flow experiments for conditions ranging from bubbly flow to cap/slug flow have been performed under isothermal concurrent air-water flow conditions in a vertical column of 3 m height. Also the liquid properties like the surface tension have varied by adding small quantities of 1-Butanol in order to see how these changes affect to the two phase flow properties. Numerical simul...