Question

For fluid mechanics in engineering

What is the common head loss equations, any trick equation that applies to most scenarios?

Also what’s the relationship between Reynolds number and turbulent/ laminar flow

Which equations is Reynolds number used for ?

Answer 1

The common head loss equations in fluid mechanics are:

1) Darcy Weisbach equation (head loss due to friction)

   here is the head loss, f is the darcy friction factor, L is the length of pipe, D is the dia of the pipe and V is the velocity of fluid.

2) Bernoulli's Equation

here v is the fluid flow speed, g is the acceleration due to gravity, z is the elevation , with the positive z-direction pointing upward – so in the direction opposite to the gravitational acceleration, p is the pressure at the chosen point, and ρ is the density of the fluid at all points in the fluid.

L= head losses

For laminar flow darcy weisbach factor f = 64/Re

Re =Reynolds number

For turbulent flow darcy weisbach factor is given by :

Reynold number is used for darcyweisbach equation.