## Flow of liquid

Flow of liquid

### Stream line flow of a liquid

Stream line flow of a liquid is that flow in which every particle of the liquid follows exactly the path of its preceding particle and has the same velocity in magnitude and direction as that of particle while crossing through the point. A stream line flow is accompanied by stream lines of liquid.

### Laminar flow

That study flow in which the liquid moves in the form of layers is called a laminar flow. In this flow, one layer slides over the other layer of liquid. The velocity of liquid flow is always less then the critical velocity of liquid.

### Stoke’s law

It states that the background dragging force F acting on a small spherical body of radius r, moving through a viscous medium of viscosity, with a viscosity v is given by F=6prv

### Bernoulli’s Theorem

1) It states that for the stream line flow of an ideal liquid, the total energy ( the sum of pressure energy, the potential energy and kinetic energy) per unit volume remains constant at every cross-section throughout the tube.

2) If the liquid is flowing through a horizontal tube, then h is constant, then Bernoulli’s Theorem states that P+1/2?v2 = a constant Thus Bernoulli’s Theorem also states that in a stream line flow of an ideal liquid through a horizontal tube, the velocity increases where pressure decreases and vice-versa.

3) Bernoulli’s Theorem is based on the law of conservation of energy.

4) It is applicable to ideal liquid i.e. a liquid which is non-viscous, irrotational and incompressible.

### Torricelli’s law

It states the velocity of efflux i.e. the velocity with which the liquid flows out of an office (i.e. a narrow hole) is equal to that which a freely falling body would acquire in falling through a vertical distance equal to the depth of below the surface of liquid. Quantitatively velocity of efflux, v is equal to in root 2gh, where h is the depth of orifice below the free surface of liquid.