Absolute viscosity of a fluid divided by its density at the same temperature of measurement. It is the measure of a fluid's resistance to flow under gravity, as determined by test method ASTM D445. To determine kinematic viscosity, a fixed volume of the test fluid is allowed to flow through a calibrated capillary tube(viscometer) that is held at a closely controlled temperature. The kinematic viscosity, in centistokes(cSt), is the product of the measured flow time in seconds and the calibration constant of the viscometer.