Collisions of Porous Clusters: : A Granular-mechanics Study of Compaction and Fragmentation

C. RINGL; E.M. BRINGA; D.S. BERTOLDI; H.M. URBASSEK

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Año: 2012 vol. 752 p. 151 - 163

0004-637X

The collision of granular clusters can result in a number of complex outcomes from sticking to partial or fulldestruction of the clusters. These outcomes will contribute to the size distribution of dust aggregates, changingtheir optical properties and their capability to contribute to solid-state astrochemistry. We study the collision oftwo clusters of equal size, formed by approximately 7000 sub-m grains each, with a mass and velocity rangethat is difficult to sample in experiments. We obtain the outcome of the collision: compaction, fragmentation, andsize distribution of ejecta, and type of outcome, as a function of velocity and impact parameter. We compare ourresults to other models and simulations, at both atomistic and continuum scales, and find some agreement togetherwith some discrepancies. We also study collision-induced compaction as a function of cluster size, up to sizes ofN = 250,000, and find that for large clusters considerably higher compactions result at higher velocities.