运动粘度 Kinematic viscosity

分类：物理编辑：尚延伟日期：2024/04/08

1 英语原文

运动粘度：Kinematic viscosity

2 单词解释 Kinematics

Kinematics, branch of physics and a subdivision of classical mechanics concerned with the geometrically possible motion of a body or system of bodies without consideration of the forces involved (i.e., causes and effects of the motions).

运动学，物理学的一个分支，也是经典力学的一个分支，涉及物体或物体系统的几何上可能的运动，而不考虑所涉及的力（即运动的原因和影响）。

Kinematics aims to provide a description of the spatial position of bodies or systems of material particles, the rate at which the particles are moving (velocity), and the rate at which their velocity is changing (acceleration). When the causative forces are disregarded, motion descriptions are possible only for particles having constrained motion—i.e., moving on determinate paths. In unconstrained, or free, motion, the forces determine the shape of the path.

运动学旨在描述材料粒子的物体或系统的空间位置、粒子运动的速率（速度）以及它们的速度变化的速率（加速度）。当忽略因果力时，运动描述只能用于具有受约束运动的粒子，即在确定的路径上移动。在无约束或自由运动中，力决定了路径的形状。

3 英文解释

Kinematic viscosity is the ratio of - absolute (or dynamic) viscosity to density - a quantity in which no force is involved. Kinematic viscosity can be obtained by dividing the absolute viscosity of a fluid with the fluid mass density like

运动粘度是绝对（或动力）粘度与密度的比值，不涉及力。运动粘度可以通过将流体的绝对粘度除以流体质量密度来获得，例如

ν = μ / ρ

where

ν = kinematic viscosity (m²/s)

μ = absolute or dynamic viscosity (N s/m²)

ρ = density (kg/m³ )

In the SI-system the theoretical unit of kinematic viscosity is m2/s - or the commonly used Stoke (St) where

1 St (Stokes) = 10-4 m²/s = 1 cm²/s

Stoke comes from the CGS (Centimetre Gram Second) unit system.

Since the Stoke is a large unit it is often divided by 100 into the smaller unit centiStoke (cSt) - where

1 St = 100 cSt

1 cSt (centiStoke) = 10-6 m²/s = 1 mm²/s