On the effect of the window size on the assessment of particle diffusion

ABSTRACT

In this work the decrease in the number of particles due to decrease in the size of the detection window on particle diffusion is investigated with the use of a numerical model of saltating grains. In order to formulate the problem, the available experimental data of particle diffusion are presented and discussed. Five different detection window sizes are investigated, showing that in both transverse and longitudinal directions the calculated dispersion of the particles noticeably decreases with the decrease in the window size. This highlights the “window” effect on the calculated variance of particle positions. The results indicate that the interpretation of the experimental data may be biased due to the “window” effect leading to potentially false conclusions about the regime of the diffusion of particles.

Keywords:

• Data interpretation
• Lagrangian model
• particle diffusion
• saltation
• sediment transport

Acknowledgements

The authors wish to thank Artur Sawicki for proof-reading the manuscript.

ORCID

Robert J. Bialik http://orcid.org/0000-0002-0254-6352

Additional information

Funding

This work was supported within statutory activities No 3841/E-41/S/2016 of the Ministry of Science and Higher Education of Poland and within the project for the Young Scientists No. 3d/IGF PAN/ 2015mł; Institute of Geophysics Polish Academy of Sciences.