Proceedings

EPJ E Highlight - Granular media friction explained: Da Vinci would be proud

Heather Shevlin / Unsplash Caption: Physicists show how solid friction affects sand grains.

New study explains how solid friction forces affect granular materials in two or more dimensions

Leonardo Da Vinci had already noticed it. There is a very peculiar dynamics of granular matter, such as dry sand or grains of wheat. When these granular particles are left on a vibrating solid surface, they are not only subject to random vibrations, they are also under the spell of solid friction forces, like the force a dry floor would exert on a brick in contact with that floor. In a study published in EPJ E, Prasenjit Das from the Jawaharlal Nehru University, India, and colleagues extended our understanding of this problem from the well-known, one-dimensional case to multiple dimensions.

The trouble with the one-dimensional case is that it does not represent physical reality. In this study, the authors have solved the equation describing the effect of solid friction on granular materials for an arbitrary number of dimensions.

First, they considered that because the particle is affected by a vibrating random force, they cannot obtain its position and velocity with certainty. Therefore, they considered the probability distribution of its position. They then used an equation - the Fokker-Planck (FP) equation - to describe its evolution.

They managed to solve this equation, and obtain relevant physical quantities that are measurable experimentally to check the validity of their solution, by employing a simple analogy with another field, that of quantum mechanics and the solution to the famous Schrodinger equation. Their results are in excellent agreement with numerical solutions in 2 and 3 dimensions.

This means that the model can also be used in further studies of a driven particle in a granular fluid, which is relevant to a number of industries, ranging from construction to pharmaceuticals. In this problem, a constant force acts on an intruder particle which interacts via two forces, namely the normal contact forces and friction forces, with the particles of the granular fluid.

Single Particle Brownian Motion with Solid Friction. P.Das, S. Puri and M. Schwartz (2017), Eur. Phys. J. E 40: 60, DOI 10.1140/epje/i2017-11549-9

This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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