Name: forces in a 180° pipe bend
Uploaded: 2025-02-13T15:43:22.000Z
Duration: 1 min 15 s
Channel: JoVE

L’eau s’écoule à travers un coude horizontal en forme de U. La section transversale de l’écoulement est de 0,01 mètre carré et l’intensité de la vitesse d’écoulement est de 15 mètres par seconde tout au long du coude.
La pression à l’entrée est de 0,2 mégapascal, et la pression à la sortie est de 0,16 mégapascal.
L’objectif est de trouver les composantes de la force d’ancrage le long des directions x et y nécessaires pour fixer le coude en place.
Ici, à l’entrée et à la sortie, l’écoulement est dans la direction y uniquement, ce qui indique que l’amplitude le long de la direction x est réduite à zéro.
L’intensité de la force du composant dans la direction y peut être obtenue en simplifiant l’expression du volume de contrôle.
La composante y de la vitesse est positive à l’entrée et négative à la sortie, tandis que le débit massique est négatif à l’entrée et positif à la sortie. Selon l’équation de continuité, le débit massique peut être considéré comme constant.
Avec l’expression du débit massique, la composante de la force dans la direction y peut être obtenue.

application de l'équation de moment linéaire

L'application de l'équation de moment linéaire peut être utilisée pour analyser les forces nécessaires pour maintenir en place un coude de tuyau à 180 degrés avec de l'eau qui coule. Dans ce cas, l'eau s'écoule à travers le coude avec une section transversale constante de 0,01 mètre carré et une vitesse d'écoulement de 15 mètres par seconde. La pression à l'entrée est de 0,2 mégapascal et la pression à la sortie est de 0,16 mégapascal.

L'objectif est de déterminer les composantes de force dans les directions x et y pour maintenir le tuyau en place. Étant donné que l'écoulement se fait uniquement dans la direction y à l'entrée et à la sortie, la force dans la direction x est nulle. La composante de force dans la direction y peut être calculée en considérant le comportement de l'écoulement à travers le volume de contrôle. La vitesse dans la direction y est positive à l'entrée et négative à la sortie, tandis que le débit massique reste constant tout au long du coude selon l'équation de continuité.

En utilisant le débit massique et en appliquant l'équation de moment linéaire, la composante y de la force d'ancrage peut être déterminée. Ce processus permet une analyse claire des forces agissant sur le coude du tuyau en raison de l'écoulement de l'eau.

Application de l'équation de moment linéaire

L’eau s’écoule à travers un coude horizontal en forme de U. La section transversale de l’écoulement est de 0,01 mètre carré et l’amplitude de l’écoulement ...

application-of-the-linear-momentum-equation

Education

Enseignement

JoVE Core

Civil Engineering

Génie civil

Unit 1

Unité 1

Finite Control Volume Analysis

Analyse par volumes de contrôle finis

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

Application of the Linear Momentum Equation

forces in a 180° pipe bend

Forces in a 180-degree pipe bend can be found by applying the linear momentum equation to flowing water. The pipe has a constant cross-sectional area of 0.01 square meters, and the water moves at 15 meters per second. The pressure at the inlet is 0.2 megapascals, and the pressure at the outlet is 0.16 megapascals.

The goal is to find the force components in the x and y directions that hold the bend in place. In this case, the flow is only in the y direction at both the entrance and the exit. That means the x-direction force is zero. The y-direction force is found by looking at the flow across the control volume, which is the region being analyzed.

The velocity in the y direction is positive at the inflow and negative at the outflow. The mass flow rate stays constant through the bend according to the continuity equation, which means mass entering equals mass leaving. Using the mass flow rate and the linear momentum equation makes it possible to calculate the anchoring force in the y direction. This gives a clear way to analyze the forces on the pipe bend caused by the water flow.

Forces in a 180° Pipe Bend

conservation of mass in finite cotrol volume

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conservation of mass in fixed, nondeforming control volume

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Continuity and Velocity in Pipe Flow

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conservation of mass in moving, nondeforming control volume

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Stormwater Detention Basin Mass Balance

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Momentum Balance for Fluid Control Volumes

Linear momentum balance for a fluid control volume links Newton’s second law to moving fluid. The law says that the rate of change of linear momentum equals the sum of the external forces acting on the system. In a fluid system, this idea helps explain how motion and force are related. A control volume can match the fluid system at a specific moment. When that happens, the forces on the control volume and the system are the same. Reynolds transport theorem explains this connection by splitting...

application of the linear momentum equation

Forces in a 180-degree pipe bend can be found by applying the linear momentum equation to flowing water. The pipe has a constant cross-sectional area of 0.01 square meters, and the water moves at 15 meters per second. The pressure at the inlet is 0.2 megapascals, and the pressure at the outlet is 0.16 megapascals. The goal is to find the force components in the x and y directions that hold the bend in place. In this case, the flow is only in the y direction at both the entrance and the exit.

moment-of-momentum equation

Wind Turbine Torque and Angular Momentum

The moment-of-momentum equation helps explain how wind turbine blades create torque. Torque is the turning effect of a force around an axis. In rotating systems, this equation links the motion of the wind with the force acting on it. The equation begins with Newton's second law for a fluid particle. That law says the rate of change of linear momentum equals the external force on the particle. To find torque, the position of the particle relative to the rotation axis is combined with that force.

conservation of energy in control volume

Turbine Work from Energy Changes

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Centrifugal Pump Flow Rate Calculation

Centrifugal pump flow rate can be calculated with the energy equation. In this problem, water moves between two reservoirs at different elevations, and the pump provides the energy needed for the transfer. The pump input is 7500 joules per second, the elevation difference is 10 meters, and the head loss from friction and other resistances is 5 meters. Both reservoirs are open to the atmosphere, so the pressure at the inlet and outlet is the same. That means the pressure terms in the energy...

design example: forces in sluice gate

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...

key terms and concepts

Use the linear momentum equation to find the x and y force components that hold a 180-degree pipe bend in place as water flows through it.

Forces in a 180° Pipe Bend | JoVE K12

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.

civil engineering

Forces in a 180° Pipe Bend

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