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

Uma comporta é uma barreira vertical que controla o fluxo de água em um canal.
Para calcular as forças que atuam em uma comporta, considere a água fluindo sob a comporta.
As forças dependem das profundidades da água a montante e a jusante.
No lado a montante, a profundidade é z1, e no lado a jusante, a profundidade é z2.
A diferença de pressão entre os dois lados cria uma força resultante no portão.
Usando o princípio de Bernoulli, a velocidade da água sob o portão, V2, pode ser calculada com base na diferença de pressão e na queda de altura.
A força de reação no portão é calculada a partir da força hidrostática que atua devido à coluna de água em ambos os lados.
A força é maior quando o portão é fechado devido à maior diferença de pressão.
Quando o portão é aberto, a força de reação diminui à medida que a água flui livremente sob o portão, reduzindo a diferença líquida de pressão hidrostática.
Este princípio permite determinar a força de ancoragem necessária para manter o portão no lugar durante a operação.

exemplo de projeto: forças em comporta

Design Example: Forces in Sluice Gate

Na engenharia hidráulica, as comportas são essenciais para gerenciar o fluxo de água por meio de canais, reservatórios e sistemas de irrigação. Comportas, agindo como barreiras verticais, regulam a água ajustando a altura de abertura da comporta, alterando a velocidade e a pressão da água fluindo abaixo da comporta. Entender as forças envolvidas é crucial para projetar comportas que podem suportar diferenças de pressão dinâmica, especialmente quando a comporta está fechada ou parcialmente aberta.

As principais variáveis ​​na análise das forças da comporta incluem a profundidade a montante z_1​ e a profundidade a jusante z_2​. Quando a comporta está fechada, a profundidade da água é maior no lado a montante, criando um diferencial de pressão significativo através da comporta. Essa diferença de pressão produz uma força líquida, que requer um sistema de ancoragem para manter a comporta firmemente no lugar. A pressão hidrostática exercida no lado a montante é proporcional à profundidade da água e à força gravitacional, enquanto a pressão a jusante depende de z_2​. O gradiente de pressão resultante através da comporta cria uma força líquida empurrando-a em direção ao lado a jusante.

Quando a comporta está parcialmente aberta, a água flui por baixo dela, e o princípio de Bernoulli pode ser usado para determinar a velocidade a jusante, V_2​.

<img alt="Equation 1" src="/files/ftp_upload/18056/18056_Equation_1.svg" style="text-align: center; height: 90px;">


Dadas as profundidades a montante e a jusante, o princípio relaciona a mudança na pressão devido às diferenças na altura da água, permitindo o cálculo de V_2 com base nas diferenças de altura e gradientes de pressão. Esse fluxo diminui a pressão exercida na comporta ao permitir o movimento em vez da acumulação, reduzindo a força líquida à medida que a água flui livremente.

 A força de reação total na comporta é influenciada principalmente pela força hidrostática da coluna de água a montante, o qual é mais alta quando a comporta está totalmente fechada. À medida que a comporta se abre e a água flui por baixo dela, a redução no diferencial de pressão diminui a força de reação.

<img alt="Equation 2" src="/files/ftp_upload/18056/18056_Equation_2.svg" style="text-align: center; height: 90px;">

Exemplo de projeto: Forças em comporta

Uma comporta é uma barreira vertical que controla o fluxo de água em um canal.
Para calcular as forças que atuam em uma comporta, considere a água que flui sob ...

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Finite Control Volume Analysis

Análise de Volume de Controle Finito

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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.

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design example: forces in sluice gate

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...

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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.

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JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

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Sluice Gate Water Pressure and Reaction Force

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