Error message

Notice: Undefined offset: 0 in include() (line 35 of /home/it/www/www-icts/sites/all/themes/riley/templates/views/views-view-fields--related-file-field-collection-view.tpl.php).
Seminar
Speaker
Akshay Bhatnagar (NORDITA- Nordic Institute for Theoretical Physics, Stockholm)
Date & Time
Mon, 25 November 2019, 11:00 to 12:30
Venue
Emmy Noether Seminar Room, ICTS Campus, Bangalore
Resources
Abstract

Turbulent flows in nature often have small particles embedded in them. Two canonical examples are gas flows in proto-planetary disks with small dust particles and air flows in a cloud with small water droplets. The first one controls the physics of the formation of planetesimals – small kilometre size objects that themselves collide and merge to form planets. The second one controls the physics of rain formation. In both these systems, small particles collide and merge to form larger objects. In order to understand this process of collision and coalescence, we study the relative motion of two nearby heavy particles advected by a turbulent flow. We find that the probability distribution of the relative velocity of two particles has a power-law tail. This indicates very high relative velocity and collision rates for the particles. We compute the joint probability distribution function (JPDF) of separation and their relative velocity. We find that at small separations this JPDF is independent of the separation, this is due to the singularities refereed as caustics, appearing in the velocity field of the particles.