FRICTIONAL LOSS IN PIPE FLOW – DARCY WEISBACK EQUATION

FRICTIONAL LOSS IN PIPE FLOW – DARCY WEISBACK EQUATION

When a liquid is flowing through a pipe, the velocity of the liquid layer adjacent to the pipe wall is zero. The velocity of liquid goes on increasing from the wall and thus velocity gradient and hence shear stresses are produced in the whole liquid due to viscosity. This viscous action causes loss of energy, which is known as frictional loss.

FRICTIONAL LOSS IN PIPE FLOW – DARCY WEISBACK EQUATION


Consider a uniform horizontal pipe having steady flow. Let 1-1, 2-2 are two sections of pipe.

FRICTIONAL LOSS IN PIPE FLOW – DARCY WEISBACK EQUATION


FRICTIONAL LOSS IN PIPE FLOW – DARCY WEISBACK EQUATION

FRICTIONAL LOSS IN PIPE FLOW – DARCY WEISBACK EQUATION


This Equation is known as Darcy – Weisbach equation, commonly used for finding loss of head due to friction in pipes.

Then f is known as a friction factor or co-efficient of friction which is a dimensionless quantity. f is not a constant but, its value depends upon the roughness condition of pipe surface and the Reynolds number of the flow.

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