A Comprehensive Sub-Grid Air Entrainment Model for RaNS Modeling of Free-Surface Bubbly Flows

Modeling Turbulent Entrainment of Air at a Free Surface

Overview In free-surface flows the turbulence in the liquid may be sufficient to disturb the surface to the point of entraining air into the flow. This process is important, for example, in water treatment where air is needed to sustain microorganisms for water purification and in rivers and streams for sustaining a healthy fish population. Air entrainment is typically engineered into spillways...

Air entrainment through free-surface cusps.

In many industrial processes, such as pouring a liquid or coating a rotating cylinder, air bubbles are entrapped inside the liquid. We propose that this is due to air being drawn into the narrow channel of a cusp singularity that generically forms on free surfaces. Since the width of the cusp is exponentially small in the driving strength, even the minute viscosity of air is enough to destroy t...

FWm_Generation and Air Entrainment ^''^'^f^tS^ Near a Free Surface %//%

The flow in a breaking wave is a t>'pe of agitation which is conducive to foam formation. The downstream wake of a surface vessel in the seaway also is characterized by a layer of foamy, agitated water near the surface, and a subsurface layer of bubbles or a bubble cloud. The purpose of this report is to discuss the basic features of foam and bubble formation, and air entrainment as these featu...

Mathematical Modeling of Bubbly Flows 1

Adaptive Modeling for Free - Surface Flows ∗

This work represents a first step towards the simulation of the motion of water in a complex hydrodynamic configuration, such as a channel network or a river delta, by means of a suitable “combination” of different mathematical models. In this framework a wide spectrum of space and time scales is involved due to the presence of physical phenomena of different nature. Ideally, moving from a hier...