Viscosity Theory | Concordia University Wisconsin

University:
Concordia University Wisconsin
Course:
PHYS 1514 | General Physics I
Academic year:

2023
Views:

40

Pages:

1
Author:

Carly Preston

MECHANICAL PROPERTIES OF MATTER VISCOSITY THEORY v x v y 1. Newton`s law of viscosity F  A 2. SI UNIT : 3. CGS UNIT : dyne-s/cm2 or poise (1 decapoise = 10 poise) 4. Dependency of viscosity of fluids (a) On temperature of fluid Ns or deca poise m2 (i) Since cohesive forces decrease with increase in temperature as increase in K.E. Therefore with the rise in temperature, the viscosity of liquids decreases. (ii) The viscosity of gases is the result of diffusion of gas molecules from one moving layer to other moving layer. Now with increase in temperature, the rate of diffusion increases. So, the viscosity also increases. Thus, the viscosity of gases increases with the rise of temperature. (b) On Pressure of fluid (i) The viscosity of liquids increases with the increase of pressure. (ii) The viscosity of gases is practically independent of pressure. (c) On nature of fluid 5. Poiseuillel`s formula Q 6. Viscous force Fv  6rv 7. Terminal velocity vT  2 2 r    g  vT  r 2 9  8. Reynolds number Re  vd  Re < 1000 laminar flow, Re > 2000 turbulent flow dV pr 4  dt 8L