What is "viscometer"

n. (context physics English) An instrument used to measure the viscosity of a liquid.

n. a measuring instrument for measuring viscosity [syn: viscosimeter]

A viscometer (also called viscosimeter) is an instrument used to measure the viscosity of a fluid. For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Viscometers only measure under one flow condition.

In general, either the fluid remains stationary and an object moves through it, or the object is stationary and the fluid moves past it. The drag caused by relative motion of the fluid and a surface is a measure of the viscosity. The flow conditions must have a sufficiently small value of Reynolds number for there to be laminar flow.

At 20.00 degrees Celsius the dynamic viscosity (kinematic viscosity x density) of water is 1.0038 mPa·s and its kinematic viscosity (product of flow time x Factor) is 1.0022 mm/s. These values are used for calibrating certain types of viscometers.