Unit km²/s square kilometre per second Kinematic Viscosity The unit km²/s (square kilometer per second) in the field of kinematic viscosity is the measurement of a fluid's resistance to flow, with a focus on the fluid's motion itself while accounting for the fluid's density. Kinematic viscosity is the ratio of dynamic viscosity to the fluid's density, and it quantifies how easily the fluid flows under its own weight or due to external forces like pressure. A higher value for kinematic viscosity indicates that the fluid has a greater resistance to flow, thereby leading to a slower movement. Conversely, a lower value indicates a lower resistance to flow, leading to faster fluid motion. The unit km²/s is used to express kinematic viscosity. A square kilometer is a unit of area that is 1000 meters on each side, and a second is a unit of time, so km²/s represents an area flow rate. This means that for every second that elapses, a certain amount of the fluid - represented by the square kilometers - spreads or moves in the container or surface it is on. For example, a fluid with a kinematic viscosity of 1 km²/s would spread or flow 1 square kilometer in one second. This unit is relatively large, and kinematic viscosity values are typically expressed in smaller units, such as the commonly used centistokes (cSt) or square millimeter per second (mm²/s).