Since F = ŋA x velocity gradient, the frictional force on an area of 10cm 2 in water at 10 oC between two layers of water 0. The coefficient of viscosity of water at 10 oC is 1.3 x 10 -3 N s m -2. From n = F/(A x velocity gradient), it follows that n may be expressed in units of newton sm -2 (N s m -2), or ‘dekapoise’. ![]() The greater the resistance to flow, the higher the viscosity, so in the previous example, the syrup has a higher viscosity than water. Molasses, for example, has a greater viscosity than water. The reciprocal of the viscosity is called the fluidity, a measure of the ease of flow. It can also be thought of as a measure of a fluid’s thickness or its resistance to objects passing through it. viscosity, resistance of a fluid (liquid or gas) to a change in shape, or movement of neighbouring portions relative to one another. ![]() Fluid mechanics has a wide range of applications in chemical engineering, mechanical, biological systems, and astrophysics. Viscosity is a measure of a fluid’s resistance to flow. In doing this a velocity profile is set up across the flow direction. since the ‘m’ cancels, the ‘unit velocity gradient’ = 1 per second. Fluid Mechanics is a branch of Physics that studies the behavior of fluid (liquids, gases, blood, and plasmas) at rest and in motion. By including viscous forces in the flow we need to introduce the no-slip boundary condition, whereby the fluid in contact with a surface takes on the same velocity as the surface the fluid is not allowed to slip along the surface. The ‘unit velocity gradient’ = 1 ms -1 change per m. thus, n may be defined as the frictional force per unit area of a liquid when it is in a region of unit velocity gradient. The unit of F is a newton, the unit of A is m 2, and the unit velocity gradient is 1 m/s per m. When different elements move with different velocities, each element tries to drag its neighbouring elements along with it. Though a property of the fluid, its effect is understood only when the fluid is in motion. The expression for the frictional force in a liquid should be contrasted with the case of solid friction, in which the frictional force is independent of the area of contact and of the relative velocity between the solid surfaces concerned.ĭefinition, Units, and Dimensions of Coefficient of Viscosity Viscosity (represented by, Greek letter mu) is a material property, unique to fluids, that measures the fluid's resistance to flow. Viscosity results from the interaction, or friction, between molecules in a fluid. ![]() Where ŋ is a constant of the liquid known as the coefficient of viscosity. Viscosity refers to the thickness of fluid.
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