Question

Explain the mechanism of how hydraulic jump dissipates a large amount of energy.

Can we determine the energy dissipation by hydraulic jump using Darcy-Weisbach equation or manning formula? Why?

Answer 1

As the motion in the hydraulic Jump is essentially turbulent, understanding the mechanism of motion and energy dissipation as during hydraulic jump water with a very high velocity enters suddenly into a low velocity zone and hence dissipation of energy occurs because the rapidly flowing liquid is abruptly slowed and increases in height, converting some of the flow's initial kinetic energy into an increase in potential energy, with some energy irreversibly lost through turbulence to heat.

No we can't use them as :

1. Darcy weisbach equation was developed to be used for the pressurized systems like pipes to calculate the frictional head loss and can't be used in open channel flow phenomenon.

2. Manings equation is used to calculate the flow velocity based on the basin characteristics it has no link to calculate energy.