If you release sand or similar granular material in a container filled with water, the material will sink to the bottom and may form a crater-like structure. Explain and investigate the phenomenon.

TYPT Supplementary References

basic

Philip T. Metzger, Robert C. Latta, Jason M. Schuler, Christopher D. Immer; Craters Formed in Granular Beds by Impinging Jets of Gas. AIP Conf. Proc. 18 June 2009; 1145 (1): 767-770.  https://doi.org/10.1063/1.3180041

W. Zhang, H. Katsuragi, and K. Yamamoto, “Drop impact on wet granular beds: Effects of water-content on cratering,” Soft Matter 20, 6120 (2024).https://doi.org/10.1039/D4SM00386A

Saingier G, Sauret A, Jop P. Falling jet of dry granular material in water. Journal of Fluid Mechanics. 2021;916:A34. doi:10.1017/jfm.2021.131

advaced

R. Krechetnikov and A. Zelnikov. Statistical mechanics of a two-dimensional quasistatic granular pile: Thermodynamics and constitutive relations. Phy. Rev. E 111 055408 (2025) https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.055408

Possible direction for doing experiment

1. Adjustable variables: rate of sand flux, cross sectional area of sand flux , height of sand relative to water surface, different granular materials, salty water of different salt density .
2. Measured quantities: height of crater, size/shape/depth of crater, symmetry of crater.

The goal is to find a trend relating different variables and measured quantities.

Craters Formed in Granular Beds by Impinging Jets of Gas

P. T. Metzger; R. C. Latta, III; J. M. Schuler; C. D. Immer. AIP Conf. Proc. 1145, 767 770 (2009).

• A jet of gas impinges vertically on a granular bed and forms a crater.
• Grains are moved by several different mechanisms: viscous erosion, diffused gas eruption, bearing capacity failure (BCF), and/or diffusion driven shearing.
• Two specific regimes are studied: viscous erosion forming scour holes as a function of particle size and gravity; and bearing capacity failure forming deep transient craters as a function of soil compaction

BCF:When the dynamic pressure of the impinging jet applies mechanical loading to the top surface of the granular bed beyond its bearing capacity and thus shoves it downward to form a depression.

Drop impact on wet granular beds: water content effects on the cratering

Wei Zhang, Hiroaki Katsuragi and Ken Yamamoto, Soft Matter 20 6120 6130 (2024).