Categorization of Brazil nut effect and its reverse under less-convective conditions for microgravity geology

Toshihiro Chujo, Osamu Mori, Junichiro Kawaguchi, Hajime Yano

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Due to its important role in the sorting of particles on microgravity bodies by size, Brazil nut effect (BNE) is a major subject of study for understanding the evolution of planetesimals. Recent studies have revealed that the mechanism for the BNE on microgravity bodies is the percolation of particles or void-filling, rather than granular convection. This study also considers the mechanism for the BNE under 'less-convective' conditions and introduces three categories of behaviour for particles that mainly depend on the dimensionless acceleration of vibration Γ (ratio of maximum acceleration to gravitational acceleration), using a simplified analytical model. The conditions for Γ proposed by the model for each category are verified by both numerical simulations and laboratory experiments. 'Less-convective' conditions are realized by reducing the friction force between particles and the wall. We found three distinct behaviours of the particles when Γ > 1: the (i) 'slow BNE', (ii) 'fast BNE', and (iii) 'fluid motion' (the reverse BNE may be induced), and the thresholds for Γ correspond well with those proposed by the simplemodel. We also applied this categorization to low-gravity environments and found that the categorization scales with gravity level. These results imply that laboratory experiments can provide knowledge of granular mobility on the surface of microgravity bodies.

Original languageEnglish
Pages (from-to)4447-4459
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - 2018 Mar 1
Externally publishedYes


  • Asteroids: general
  • Comets: general
  • Methods: analytical
  • Methods: laboratory: atomic
  • Methods: numerical
  • Minor planets

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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