Fluid Motion

Written by Isha. Posted in Arts & Science on 01 December 2011.
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Fluid Motion

Fluid motion deals with nature of flow of liquid.Fluid motion consists of several subcategories like aerodynamics and hydrodynamics which are used in several applications like motion of aircrafts and motion of water in pipelines.

Fluid consists of various types of flow based on its motion These are explained below:

Streamline Flow:The motion of fluid in which following particle traces the path with same velocity at same time of the preceding particle.In other words we can say that each particle follows the motion of preceding particle.There are no irregularities in motion and particles change their speed in a regular discipline.


Laminar Flow :The flow of liquid in which it flows in the form of layers but in constant direction means there is not zig-zag motion of particles in this flow. It is same as streamline flow.

Turbulent Flow:The flow of liquid in which particles move in random directions.There is no particular flow of liquid particles.this flow consists of high diffusion i.e. intermixing of particles and irregularities.Flow of air or flow of water in river is turbulent flow.In this kind of flow direction and magnitude of velocities of particles varies at every instant of time.

Terminal Velocity:When we throw an object in liquid in the initially it moves with high speed due to its wait acting downward but as liquid applies an opposite force in upward side the object starts moving with constant velocity which is called terminal velocity.Velocity of an object becomes its terminal velocity in any fluid when its gravitational attractive force becomes equal to the thrust applied by liquid .In that case freely falling object starts moving with constant velocity.Terminal velocity gained by an object depends on its weight and thrust i.e. upwards force . More the weight is more the terminal velocity,more the thrust less is terminal velocity.

180px-Terminal Velocity

Bernoulli's Theorem : Bernoulli's theorem stated that For an ideal(ideal refers to incompressible and non viscous) liquid with streamline flow sum of all energies(pressure energy,potential energy,kinetic energy) remains constant at all points in same time. Its equation is : P/p + gh + 1/2 v^2 = constant. Bernoulli's theorem can be derived from principle of conservation of energy and Newton's second law of motion.

Application of Bernoulli's Theorem:

1.During the motion of aircraft speed of air on upper of aeroplane is more than lower side wings .here Bernoulli's theorem applied as pressure on the lower side is more than upper side which gives up thrust to aeroplane to fly away. 2.During the storms roofs of kutcha house moves away because due to more air speed on the upside of roof the pressure on the upside decreases and increases on the lower side which applies a thrust on roof tends to move the roof from its place.

Viscosity :Viscosity is defined as an internal resistance or opposition applied by a layers on each other to resist motion.It is same as friction.More the denser fluid is more is the viscosity.Viscosity can be decreased by heating the fluids as it increase the motion of particles of fluids which tends to reduce the viscosity.Viscosity is measured by different types of viscometers and rheometers.


Author: Isha

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