Two tubes are immersed in a vessel holding sand and are similar except that the end of one of the tubes is bent. The top and bottom ends of the tubes are open.

1. The tubes are empty. When the vessel vibrates, the bent tube is filled with sand, i.e., the granular material behaves like a liquid, while the straight tube remains empty and the material in it behaves differently.

2. The tubes are filled with sand. Under vibrations, the material flows from the straight tube into the vessel until it is almost completely empty, i.e., the straight tube acts as a vibration pump. At the same time, no changes are registered in the bent tube, as it remains filled.

The effects are observed both when the tubes are rigidly connected to the vessel and when they are generally fixed. The physical explanation and mathematical description for the phenomena are given in [1] and book [2]. Other effects demonstrating the peculiar behavior of a granular medium in communicating vibrating vessels are covered in [3, 4].

References

1. Blekhman I. I., Vaisberg L. A., Blekhman L. I., Vasilkov V. B., Yakimova K. S. On certain “anomalous” effects in the behavior of a granular medium in communicating vibrating vessels // Obogashchenie Rud (Mineral Processing Journal). 2007. No. 5. pp. 36–40.
2. Blekhman I. I. Vibrational Mechanics and Vibrational Rheology (Theory and Applications). Moscow. Fizmatlit. 2018.
3. Lipovsky M. I. On a type of vibrational displacement of a granular medium // Proceedings of the USSR Academy of Sciences, Solid Body Mechanics. 1969. No. 3. pp. 6–9.
4. Kremer E. B., Palilov V. F., Shifrina E. B. Behavior of a granular material in vibrating communicating vessels // New Areas in Raw Material Processing and Industrial Waste Recycling: Collection of Research Papers / Mekhanobr. Leningrad. 1986. pp. 31–44.