Define and explain uniform flow. How is open channel flow different from pipe flow?

 

Uniform flow 

a.      Uniform flow means fluid flowing with the constant velocity at different sections at a given time period. Flow of a fluid in which each particle moves along its line of flow with constant speed and in which the cross section of each stream tube remains unchange. In uniform flow, the particle moves along its line of flow with constant speed and in which the cross section of each stream tube remains unchanged.

 

Open-channel flow, a branch of hydraulics and fluid mechanics, is a type of liquid flow within a conduit or in channel with a free surface, known as a channel.^[1][2] The other type of flow within a conduit is pipe flow. These two types of flow are similar in many ways but differ in one important respect: the free surface. Open-channel flow has a free surface, whereas pipe flow does not

               

The main difference open channel flow and pipe flows is the boundary conditions and the free surface of the liquid.

1. Open Channel flow:

Ø Open channel flows are characterised by a free surface (usually) open to the atmosphere.

Ø Open channel flows examples are streams, rivers, artificial canals, irrigation ditches, flumes, pipe-lines, culverts, tunnels, sewer lines, gutters, domestic draining boards.

2. Pipe or duct flow:

Ø All of the cross-section is taken up with the fluid. This is referred to as a "closed conduit".

Ø The energy in pipe flow is expressed as head and is defined by the Bernoulli equation