Sluice Gate Flashcards
When can the Bernoulli equation be used in the context of sluice gates, and what conditions are assumed?
The Bernoulli equation can be used when the flow accelerates, and energy losses are small. It assumes horizontal streamlines in cross-sections 1 and 2 and that the piezometric head is equal to the local water depth
What is the iterative solution strategy for analyzing flow through a sluice gate?
The iterative solution strategy involves using an estimate for one of the terms on the left-hand side of the equation and using the equation to find an improved estimate.
How do you initially estimate the piezometric head
h for sub-critical and super-critical flows in sluice gate analysis?
For super-critical flow, use
h= 0 as the initial estimate. For sub-critical flow, use h=H, where
H represents the depth that corresponds to most of the energy head
What is the significance of keeping a large expected term on the left-hand side of the equation in sluice gate flow analysis?
Keeping the large expected term on the left-hand side helps in making accurate iterative calculations by focusing on the most significant aspect of the flow’s energy
How does the flow type affect the initial estimation in the iterative solution for sluice gate flow analysis?
The flow type (sub-critical vs. super-critical) affects the initial estimation by determining which term (piezometric head or velocity head) is used as a starting point for iterative calculations, reflecting the most significant component of the flow’s energy for each flow type.
What happens to the water level when there is a restriction in channel width, specifically when the width reduction results in
h2<h1?
When there is a restriction in channel width resulting in
h2<h1, it means the water level between the bridge piers has reduced due to the width reduction
How does a reduction in channel width affect the velocity and piezometric head of the water flow?
A reduction in channel width causes a larger velocity in the water flow. Consequently, the water level (piezometric head) decreases to ensure the energy head remains constant
Why must the piezometric head decrease when the channel width is reduced and the velocity increases?
he piezometric head must decrease to balance the increase in velocity, ensuring that the total energy head of the flow remains constant despite the restriction in channel width.
What term will be large in a subcritical flow?
h2_new -> piezometric head
What term will be larger in a supercritical flow?
⍺/(h2_new)^2 -> velcoity head
If you expect downstream flow to be supercritical what value of h_old do you use?
0
When energy head is plotted as a function of water depth, what is it called?
Energy diagram
