define Viscosity surface tension and vapour pressure and explain their influence fluid motion
Answers
Answer:
Surface Tension is the property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules. Viscosity is a resistance of a fluid (liquid or gas) to a change in shape, or movement of neighbouring portions relative to one another.
Explanation:
For example, oil has a high viscosity, but when we put it in the car and heat it up, it becomes less viscous and thus flows smoothly through an engine and other parts of the car. Higher the viscosity, slow will be the liquid flow. Viscosity decreases with increase in temperature, with some exceptions.
Viscosity is sometimes also understood as frictional forces that act in between fluid and the surface of contact. The surface can either be a solid surface like a pipe and water can be the fluid. Now the resistance provided by the pipe to the water flow is viscosity. However, viscosity can also arise in between two fluids flowing at different velocities.
The above phenomenon of viscosity is very much particular to liquid, to be precise Newtonian fluids. However, in the case of non-Newtonian fluids, the interactions are quite bizarre and are always hard to model and understand.
It has no component perpendicular to the horizontal surface. As a result, there is no pressure difference between the liquid side and the vapour side. ... Thus, there is always an excess of pressure on the concave side of a curved liquid surface over the pressure on its convex side due to surface tension.