Free settling

… In a group of particles with the same density but different sizes, if the concentration of the particles dispersed in the liquid is low and the particles do not affect each other, and if the particle diameter is small compared to the size of the container and can be considered not to be affected by the container wall, the larger particles will sink before the smaller particles, causing a change in concentration in the direction of the container depth. This phenomenon is called free settling. The phenomenon in which larger particles sink faster than smaller particles among particles of the same density is due to the difference in sedimentation velocity. …

*Some of the terminology explanations that mention "free settling" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…　密度が同一で大きさの異なる粒子群において，液体中に分散している粒子の濃度が希薄で粒子が互いの影響を受けず，かつ粒子径が容器の大きさに比べて小さく器壁の影響を受けないとみなせるならば，大きな粒子は小さな粒子より先に沈み，容器の深さ方向に濃度変化を生ずる。このような現象を自由沈降free settlingという。同じ密度の粒子間で，粒子径の大きいほうが小さい粒子より速く沈む現象は，沈降速度sedimentation velocityの差によるものである。…

※「free settling」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報