Name: sluice gate water pressure and reaction force
Uploaded: 2025-02-13T15:43:22.000Z
Duration: 1 min 11 s
Channel: JoVE

A sluice gate is a vertical barrier that controls water flow in a channel.
To calculate the forces acting on a sluice gate, consider water flowing under the gate.
The forces depend on the upstream and downstream water depths.
On the upstream side, the depth is z1, and on the downstream side, the depth is z2.
The difference in pressure between the two sides creates a net force on the gate.
Using Bernoulli&#39;s principle, the water&#39;s velocity under the gate, V2, can be calculated based on the pressure difference and height drop.
The reaction force on the gate is computed from the hydrostatic force acting due to the water column on both sides.
The force is larger when the gate is closed because of the greater pressure difference.
When the gate is opened, the reaction force decreases as water flows freely under the gate, reducing the net hydrostatic pressure difference.
This principle allows for the determination of the anchoring force required to keep the gate in place during operation.

design example: forces in sluice gate

Design Example: Forces in Sluice Gate

In hydraulic engineering, sluice gates are essential for managing water flow through channels, reservoirs, and irrigation systems. Sluice gates, acting as vertical barriers, regulate water by adjusting the gate's opening height, which changes the velocity and pressure of water flowing beneath the gate. Understanding the forces involved is crucial to designing sluice gates that can withstand dynamic pressure differences, especially when the gate is closed or partially open.
Key variables in analyzing sluice gate forces include the upstream depth z1, and the downstream depth z2. When the gate is closed, the water depth is greater on the upstream side, creating a significant pressure differential across the gate. This pressure difference produces a net force, which requires an anchoring system to keep the gate securely in place. The hydrostatic pressure exerted on the upstream side is proportional to the water depth and gravitational force, while the downstream pressure depends on z2. The resulting pressure gradient across the gate creates a net force pushing against it toward the downstream side.
When the sluice gate is partially open, water flows beneath it, and Bernoulli's principle can be used to determine the downstream velocity, V2.
<img alt="Bernoulli's equation, fluid dynamics formula, velocity calculation equations for physics analysis." src="/files/ftp_upload/18056/18056_Equation_1.svg" style="text-align: center; height: 90px;" data-altupdatedat="1762173717000" data-alt="Equation 1" />
Given the upstream and downstream depths, the principle relates the change in pressure due to differences in water height, allowing for calculating V2 based on height differences and pressure gradients. This flow decreases the pressure exerted on the gate by allowing movement rather than accumulation, reducing the net force as water flows freely.
The total reaction force on the sluice gate is mainly influenced by the hydrostatic force from the upstream water column, which is at its highest when the gate is fully closed. As the gate opens and water flows beneath it, the reduction in pressure differential lowers the reaction force.
<img alt="Fluid static equilibrium equations; mathematical concepts in pressure difference; formula illustration." src="/files/ftp_upload/18056/18056_Equation_2.svg" style="text-align: center; height: 90px;" data-altupdatedat="1762173717000" data-alt="Equation 2" />

A sluice gate is a vertical barrier that controls water flow in a channel.
To calculate the forces acting on a sluice gate, consider water flowing under ...

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JoVE Core

Civil Engineering

Unit 1

Finite Control Volume Analysis

KEY TERMS AND CONCEPTS

sluice gate water pressure and reaction force

Sluice gates control water flow in channels, reservoirs, and irrigation systems. They work as vertical barriers with an opening that can be raised or lowered. Changing the opening height changes the water velocity and pressure below the gate.

The forces on a sluice gate depend on the water depths upstream and downstream, written as z1 and z2. When the gate is closed, the upstream water depth is greater. That creates a strong pressure difference across the gate and a net force toward the downstream side. In that case, the gate needs an anchoring system to keep it secure.

The pressure on the upstream side is hydrostatic pressure, which depends on water depth and gravity. The downstream pressure depends on z2. Together, these pressures create the pressure gradient that pushes on the gate.

When the sluice gate is partially open, water flows beneath it. Bernoulli's principle can then be used to find the downstream velocity, V2, from the upstream and downstream depths. As the water moves through the opening instead of building up, the pressure difference becomes smaller and the reaction force on the gate decreases. The total reaction force is therefore highest when the gate is fully closed and lower as the gate opens.

Sluice Gate Water Pressure and Reaction Force

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Sluice gates control water flow in channels, reservoirs, and irrigation systems. They work as vertical barriers with an opening that can be raised or lowered. Changing the opening height changes the water velocity and pressure below the gate. The forces on a sluice gate depend on the water depths upstream and downstream, written as z1 and z2. When the gate is closed, the upstream water depth is greater. That creates a strong pressure difference across the gate and a net force toward the...

key terms and concepts

Learn how upstream and downstream water depths affect pressure, flow speed, and reaction force on a sluice gate when it is closed or partially open.

Sluice Gate Water Pressure and Reaction Force | JoVE K12

JoVE Core Civil Engineering offers a foundational exploration of essential construction materials such as bricks, stones, steel, wood, and concrete, along with fluid mechanics topics like flow over immersed bodies, open channel flow, and dimensional modeling. It also covers key surveying concepts, including leveling, traverse adjustments, curve design, topographic mapping, and geospatial technologies (GPS & GIS). Science-in-action videos showcase laboratory research on materials, fluids, and surveying practices in real-world engineering systems.

Sluice Gate Water Pressure and Reaction Force

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