University:
North Idaho College
Course:
PHYS-211 | Engineering Physics I
Academic year:

2023
Views:

220

Pages:

4
Author:

Hani T.

Viscosity The resistance to flow offered by liquids is known as the viscosity. Liquids show a wide variation in their viscosities. Easy flow is characterized by low viscosities while high viscosities mean slow speeds of flow. Consider a liquid flowing through a pipe. The flow is from left to right. All layers of the liquid do not flow with equal velocity, layers close to the wall move very slowly while in the center of the Tube, The liquid moves with maximum velocity pipe Liquid Flow Thus, each layer moving faster than a Layer closer To the wall will experience /retardation - which is Known as viscosity Text from the image: Viscosity is defined as the force per unit area required to maintain unit difference of velocity between two layers in the liquid unit distance apart. As with gases, the coefficient of viscosity η may be defined as the force per unit area required to maintain unit difference in velocity between two layers of the liquid unit distance apart. If A is the area of the layer, dx the distance between them, and du the velocity difference, then the tangential force required to maintain a constant velocity difference du is directly proportional to A and du, and inversely proportional to dx. F ∝ A du / dx F = [ηA du] / dx η proportionality constant 1/η is called the fluidity.