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.

Background reading from IYPT reference kit

Подводный кратер (youtube, Никита Черников, 08.07.2025), https://youtube.com/shorts/qAPqEtucVPo R. Krechetnikov and A. Zelnikov. Physics of a granular pile. Phys.Rev.E 111, 5, 055408 (2025), https://doi.org/10.1103/PhysRevE.111.055408, arXiv:2405.10958 [cond-mat.soft] T. Kempe and J. Fröhlich. Collision modelling for the interface-resolved simulation of spherical particles in viscous fluids. J. Fluid Mech. 709, 445-489 (2012), https://doi.org/10.1017/jfm.2012.343 P. T. Metzger, R. C. Latta III, J. M. Schuler, and C. D. Immer. Craters formed in granular beds by impinging jets of gas. AIP Conf. Proc. 1145, 1, 767-770 (2009), https://doi.org/10.1063/1.3180041, arXiv:0905.4851 [cond-mat.soft] A. M. Ardekani, S. Dabiri, and R. H. Rangel. Collision of multi-particle and general shape objects in a viscous fluid. J. Comput. Phys. 227, 24, 10094-10107 (2008), https://doi.org/10.1016/j.jcp.2008.08.014 N. Lukerchenko, Y. Kvurt, Z. Chara, and P. Vlasak. Collision of a rotating spherical particle with flat wall in liquid (Proc. 18th Int. Conf. ENGINEERING MECHANICS 2012, Svratka, Czech Republic, May 14–17, 2012), pp. 835–841, https://engmech.cz/2012/proceedings/pdf/306_Lukerchenko_N-FT.pdf J. Einarsson. Orientational dynamics of small non-spherical particles in fluid flows (Univ. of Gothenburg, 2013), https://gupea.ub.gu.se/bitstream/handle/2077/34320/gupea_2077_34320_2.pdf

R. M. Valladares, P. Goldstein, C. Stern, and A. Calles. Simulation of the motion of a sphere through a viscous fluid. Rev. mex. fis. 49, 2, 166-174 (2003), https://www.scielo.org.mx/pdf/rmf/v49n2/v49n2a9.pdf

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