Coefficient of kinematic viscosity

…
[Motion and Viscosity]
The effect of viscosity on objects moving through a fluid or flows in pipes is determined by the Reynolds number R e = UL / ν , which is the ratio of the force due to the inertia of the fluid (approximately ρ U ² per unit area, where ρ is the density of the fluid and U is the characteristic velocity) to the viscous _force τ (approximately μ U / L, where L is the characteristic length of the object). Here, ν is the viscosity coefficient μ divided by the density ρ, and is called the kinematic viscosity, and its units are Stokes St (1St = 1cm2/s) in the CGS system and m2/s in the SI system. Therefore, kinematic viscosity is more often of concern when it comes to motion than ordinary viscosity. …

*Some of the terminology that refers to "coefficient of kinematic viscosity" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…
［運動と粘性］
　粘性が流体中を運動する物体や管内の流れなどに及ぼす効果は，流体の慣性による力(流体の密度をρ，代表速度をUとするとき，単位面積当りρU²の程度)と，粘性力τ(物体の代表長さをLとするときμU/Lの程度)の比であるレーノルズ数R_e＝UL/νで定まる。ここでνは粘性率μを密度ρで割ったもので，動粘性率(動粘度)coefficient of kinematic viscosityと呼ばれ，単位はCGS単位系ではストークスSt(1St＝1cm2/s)，SI単位系ではm2/sである。したがって運動に対してはふつうの粘性率よりも動粘性率のほうが問題になることが多い。…

※「coefficient of kinematic viscosity」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