Question

Class: Hydraulic Engineering

Hydraulic Jumps and how to calculate and how to protect dam spillways from
water jump effects?

Answer 1

● Hydraulic jump is standing wave formed when the depth of water changes from supercritical to subcritical state.

It means that that when water is comes with less height and sudden water depth increases then the phenonmen of hydraulic jump can found.

● Hydraulic Jump Calculations

y2/y1 = (1/2)[-1 + √(1 + 8Fr12)]

V1= Q/(by1)

Fr1 = V1/√(y1g)

upstream velocity = V1

upstream Froude number = Fr1,

●By Use of the last two equations, downstream depth of flow, y2 can be calculated.

●There are several devices which are construxted downstream of the spillways for energy dissipation like stilling basins and chutes.

So by construction of these devices at downstream end effect of jumps can be reduce.

stilling basin are devices which absorb or dissipate the energy from the spillway discharge and protects spillway down stream end from erosion.

thank you.