Viscosity Viscosity is a measure of a fluid's resistance to flow. It is typically measured in units of poise (Pa·s) or centipoise (cp). Viscosity depends on...
Viscosity
Viscosity is a measure of a fluid's resistance to flow. It is typically measured in units of poise (Pa·s) or centipoise (cp). Viscosity depends on several factors, including the temperature, pressure, and composition of the fluid.
Poiseuille's Formula
Poiseuille's formula is a mathematical equation that describes the flow of a fluid through a pipe. The formula states that the flow velocity of a fluid in a pipe is proportional to the square of the pipe diameter and inversely proportional to the viscosity of the fluid.
where:
v is the flow velocity
d is the pipe diameter
η is the viscosity
n is a dimensionless coefficient
Stokes' Law
Stokes' law states that the drag on a body moving through a fluid is proportional to the velocity of the fluid. The drag force is given by the formula:
where:
F_d is the drag force
b is a constant that depends on the shape of the body
v is the velocity of the fluid
r is the radius of the body
Terminal Velocity
Terminal velocity is the velocity that a fluid reaches when it flows through a pipe of infinite diameter. As the pipe diameter approaches infinity, the terminal velocity approaches the velocity of the fluid at the pipe's entrance