Measuring droplet collision in turbulence EuHIT Funded Project

Team

Gregory Bewley
Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
Kelken Chang
University of Gothenburg, Gothenburg, Sweden
John M Lawson
Max Planck Institute for Dynamics and Self-Organisation, Goettingen, Germany
Jan Molacek
Max Planck Institute, Göttingen, Germany
ewe-wei saw
CEA - Saclay, Gif sur Yvette, France

Overview

Research Infrastructure
Max Planck High-Turbulence Facility, Germany
Facilities used
von Karman Flow Apparatus (GTF3)
Project leader
Bernhard Mehlig
University of Gothenburg, Gothenburg, Sweden

Abstract

Collisions occur in atmospheric clouds and causes micron-sized water droplets to grow. Very few measurements have been made to detect these events, and little is known about how turbulence causes collisions, whether collisions lead to coalescence or break-up. In order to answers these questions, it is necessary to measure the distribution of radial relative velocities of droplet pairs, separated on scales on the order of the Kolmogorov length. The GTF3 is a unique facility that will allow us to obtain trajectories of droplets in very small measurement volume. We have developed a linear stereomatching model that fits well with previous measurements obtained in the same facility. We propose to apply this model to highly-resolved trajectories of droplets in a new experiment. As a proxy for the actual collision, we will look for droplets with approaching velocities, separated on the order of the Kolmogorov length. In a parallel effort, we will explore the possibility of using chemiluminescence and bioluminiscencein in collision experiment.