Kinematic viscosity,Cavitation,Surface Tension,Capillarity

• Kinematic viscosity is defined as the ratio of dynamic viscosity to density. n = m / r The unit of kinematic viscosity is m2/s .

• In flowing fluid, if the pressure is equal to or less than the saturated vapor pressure, the liquid boil locally and produce vapor bubbles. These bubbles collapse in the high pressure region causing a partial vaccum. This phenomenon in known as cavitation. 

• A free surface of the liquid is always under stretched condition implying the existence of tensile force on the surface. The magnitude of this force per unit length of an imaginary line drawn along the liquid surface is known as surface tension. The unit of surface tension is N/m. 

• Capillary implies the raise or depression of liquid in a capillary tube where it is held vertically or inclined in the liquid.