Dense packings of spheres in cylinders I. Simulations

TL;DR

This paper investigates the densest arrangements of hard spheres within infinitely long cylinders using simulations, extending previous work to include internal spheres not touching the cylinder surface.

Contribution

It provides detailed simulation results and structural descriptions for sphere packings in cylinders up to a diameter ratio of 2.873, including new configurations with internal spheres.

Findings

Identified densest sphere packings up to D/d=2.873

Extended understanding of internal sphere arrangements

Compared sphere packings with disk packings on cylindrical surfaces

Abstract

We study the optimal packing of hard spheres in an infinitely long cylinder, using simulated annealing, and compare our results with the analogous problem of packing disks on the unrolled surface of a cylinder. The densest structures are described and tabulated in detail up to D/d=2.873 (ratio of cylinder and sphere diameters). This extends previous computations into the range of structures which include internal spheres that are not in contact with the cylinder.