Particles in Turbulence

Particles in turbulence are omnipresent in natural and industrial systems. Rain, sandstorms and clouds are natural examples, as well as the presence of phytoplankton in the oceans. Industrial examples include sprays, mixing in chemical reactors and dust coming out from industrial chimneys.  In particular, the prediction of clouds in nature containing ash, sand, snow, rain and/or pollutants has big environmental and societal impacts. 

 

Particles that do not follow the flow, that is, that have a velocity that is different from that of the flow, are called inertial particles. They can have a large size or density compared to the flow’s, and because of their own “independent” velocity and other mechanisms, they tend to become unmixed, as opposed to other kinds of particles that tend to get mixed in turbulent flows. What I mean by this is that inertial particles tend to concentrate inhomogeneously throughout the flow, generating clusters and voids. Have you ever thought why we have isolated clouds instead of the whole sky covered in them? It’s because particles are clustered in certain regions of the atmosphere. Another anthropogenic example includes garbage islands, which is where garbage gets accumulated in the ocean (think of that the next time you throw out a non-degradable material!). 

 

I have studied inertial particles under the effect of gravity, which means that not only the do not follow the flow and have their own velocity, but they also feel the effects of a gravitational force (e.g., that of the Earth). 

 

My MSc. Thesis was based on this, and this work has been published in Physical Review Letters (please feel free to ask me for either manuscript!). I am also currently working in other related projects aimed at understanding other aspects of particles in turbulent flows, such as the interplay between gravity and the density of the particles and how they are dispersed.