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On a slanting surface, place some drops of water on one side and some drips of honey on the other. Return to the scene and monitor the flow of both liquids. You’ll see that water moves fairly quickly, whereas honey is more difficult to move. Honey is considered viscous in this scenario.
As a result, viscosity is defined as the ratio of the force necessary to transfer neighboring liquid layers over one another.
What is a Viscous Gradient, and how does it work?
The viscous gradient is the differential in velocity between the fluid layers close to each other. The viscous gradient will be greater if the higher layer applies more force to move ahead. It is denoted as v/x, where v is the velocity differential and x denotes the distance difference between the two layers. As a result, the larger the v/x number, the greater the viscous gradient.
Viscosity Coefficient
The coefficient of viscosity is the ratio of the shearing force to the fluid’s velocity gradient.As a result, the viscosity coefficient is given by,
- d / A.v = F. d / A.v
F is the tangential force required to maintain a unit velocity gradient between two parallel liquid layers of equal area.
The velocity is denoted by the letter v.
A refers to the location.
The distance between the two layers of liquid skidding over each other is denoted by the letter d.
The velocity gradient is defined as the differential in velocity between neighboring layers of a fluid stream.
The viscosity of gas is lower than that of liquid.
Coefficient of Viscosity (SI Unit)
Every liquid has a unique viscosity, and the coefficient of viscosity is a measurement of this property.The tangential force F necessary to maintain a unit velocity gradient between two parallel layers of liquid of unit area A is defined as the coefficient of viscosity.
Newton-second per square meter (Ns. m -2) is the SI unit of.
Pascal-seconds are a unit of time (Pa .s)As a result, the viscosity coefficient is a measure of the fluid’s resistance to deformation at a given rate due to internal friction.
Unit of Viscosity Coefficient
The coefficient of viscosity is measured in centimeter-gram-seconds (CGS).
dyne-sec/ cm 2 is the same as Poise.
One poise equals exactly 0.1 Pa.
Kilogram per meter per second or MKS is the meter-kilogram-second unit.
m -1 s -1 kg m -1 s -1 kg m -1 s -1 kg m
Unit of Viscosity Coefficient and Dimension
Since the coefficient of viscosity is calculated using the formula,
v = MLT2. L / L2. LT1= F. d/ A.v = F. d/ A.v = F. d/ A.v = F. d/ A.v = F. d/ A.v = F. d/ A.
We get, when we solve,
Water’s Viscosity in SI Units
Poiseuille’s law can be used to calculate the coefficient of viscosity of water.The volume of liquid flowing through a capillary tube in a unit of time is calculated using Poiseuille’s equation for liquid flow.
The formula for Poiseuille’s formula is as follows
The rate of flow of a viscous liquid through a tube with a length of ‘l’ and a radius of ” is proportional to the applied pressure P in this case.
The viscous liquid’s rate of flow is proportional to the fourth power of the tube’s inner radius and inversely proportional to the liquid’s viscosity and the tube’s length.
The coefficient of viscosity of water is calculated using the formula,
V denotes the rate at which a volume of liquid flows.
The pressure that would be applied to the liquid denoted by P is the capillary tube’s inner radius in millimeters.
The capillary tube’s length is l.The SI unit for water viscosity is Ns.m-² or Pa.s.
Conclusion
The dynamic viscosity of water at room temperature of 250°C has the following values.The value of viscosity in SI units is 8.90 10 – 4 Pas.The viscosity value in CGS units is 8.90 x 10 – 3 dyns/cm 2 or 0.890 cP.As a result, the viscosity of water is 0.0091 poise.The terms viscosity and density are used interchangeably, with viscosity referring to the fluid’s thickness and density to the space between its particles.
