Name: pitot-static measurement in bernoulli flow
Uploaded: 2026-01-30T03:08:30.000Z
Duration: 1 min 24 s
Channel: JoVE

Le principe de Bernoulli stipule que la pression totale reste constante le long d'une rationalisation dans un système fluide et est la somme des pressions statiques, dynamiques et d'énergie potentielle.
La pression statique est la force exercée par un fluide au repos, couramment observée dans les canalisations et les systèmes d’approvisionnement en eau.
Il dépend de la hauteur et de la densité du fluide et agit perpendiculairement à la surface en contact avec le fluide.
La pression dynamique est liée à la vitesse du fluide et représente l'énergie due au mouvement.
Il est crucial dans la conception de systèmes impliquant des fluides en mouvement rapide, tels que le drainage des eaux pluviales ou les canaux fluviaux à grande vitesse.
La pression de stagnation se produit lorsque le fluide est mis au repos, en combinant des pressions statiques et dynamiques.
Elle est mesurée à des points de stagnation, comme les surfaces des barrages ou les pales de turbine, où la vitesse du fluide est réduite à zéro.
Comprendre l’équilibre entre les pressions statiques, dynamiques et de stagnation permet de gérer les changements de pression et d’énergie dans les systèmes fluides.
Ces pressions sont mesurées à l’aide d’appareils tels que les tubes statiques de Pitot, essentiels pour les calculs de vitesse et d’écoulement des fluides dans diverses applications de génie civil.

pression statique, stagnante, dynamique et totale

Le concept de pression statique, stagnante, dynamique et totale est fondamental en dynamique des fluides, souvent expliqué à l'aide de l'équation de Bernoulli:

<img alt="Equation 1" src="/files/ftp_upload/18036/18036_Equation_1.svg" style="text-align: center; height: 26px;">

Ici, p est la pression statique, 1/2⍴V^2 est la pression dynamique, γz est la pression hydrostatique ou pression d'énergie potentielle, et p_T est la pression totale, constante le long d'une ligne de courant pour les écoulements incompressibles.

<ol style="display: flex; flex-direction: column; gap: 10px;">

<li>Pression statique (p): il s'agit de la pression exercée par un fluide au repos ou comme si le fluide en écoulement était amené au repos dans la direction du mouvement. Elle est mesurée à l'aide d'une sonde insérée dans l'écoulement ou par un tube piézométrique.</li>

<li>Pression dynamique (1/2⍴V^2): elle représente l'augmentation de pression due à la vitesse du fluide. Elle peut être interprétée comme l'énergie cinétique par unité de volume du fluide.</li>

<li>Pression de stagnation (p_s): il s'agit de la somme des pressions statique et dynamique à un point de stagnation, où la vitesse du fluide devient nulle:</li>

<img alt="Equation 2" src="/files/ftp_upload/18036/18036_Equation_2.svg" style="text-align: center; height: 26px;">

<li>Pression totale (p_T): il s'agit de la somme des pressions statique, dynamique et hydrostatique. Le long d'une ligne de courant:</li>

</ol>

Un tube de Pitot-statique mesure la pression de stagnation (p_s) et la pression statique (p). En calculant la différence, la vitesse du fluide peut être déterminée:

<img alt="Equation 3" src="/files/ftp_upload/18036/18036_Equation_3.svg" style="text-align: center; height: 34px;">

Dans des applications telles que la mesure de la vitesse de l'air dans l'aviation, il est essentiel de garantir un alignement et un placement précis du tube de Pitot-statique. Un mauvais alignement ou un blocage peut entraîner des lectures erronées, ce qui a un impact sur la sécurité opérationnelle.

Pression statique, stagnante, dynamique et totale

Le principe de Bernoulli stipule que la pression totale reste constante le long d'un courant dans un système fluide et est la somme de statique, dynamique et ...

static-stagnation-dynamic-and-total-pressure

Education

Enseignement

JoVE Core

Civil Engineering

Génie civil

Unit 1

Unité 1

Fluid Dynamics

Dynamique des fluides

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

Static, Stagnation, Dynamic and Total Pressure

pitot-static measurement in bernoulli flow

Static pressure, dynamic pressure, stagnation pressure, and total pressure are key ideas in fluid dynamics. They are often explained with Bernoulli's equation. In that equation, p is static pressure, 1/2ρV^2 is dynamic pressure, γz is hydrostatic pressure or potential energy pressure, and pT is total pressure. For incompressible flow, the total pressure stays constant along a streamline.

Static pressure is the pressure a fluid exerts when it is at rest, or when flowing fluid is brought to rest in the direction of motion. It can be measured with a probe placed in the flow or with a piezometer tube. Dynamic pressure comes from the fluid's speed. It represents the pressure rise due to motion, and it can also be viewed as the kinetic energy per unit volume of the fluid.

Stagnation pressure is the pressure at a stagnation point, where the fluid velocity becomes zero. It equals the sum of static pressure and dynamic pressure. Total pressure includes static, dynamic, and hydrostatic pressure. Along a streamline, this total remains constant for incompressible flow.

A Pitot-static tube measures stagnation pressure and static pressure. The difference between these two readings can be used to determine fluid velocity. This measurement is important in applications such as airspeed sensing in aviation. For accurate results, the Pitot-static tube must be aligned and placed correctly, because misalignment or blockage can produce incorrect readings and affect safety.

Pitot-Static Measurement in Bernoulli Flow

pitot-static-measurement-in-bernoulli-flow

bernoulli's equation for flow along a streamline

bernoulli-s-equation-for-flow-along-a-streamline

Pressure and Speed in Bernoulli's Equation

Bernoulli's equation links pressure, speed, and height in a moving fluid along a streamline. It is used for incompressible, inviscid fluids under steady flow. The idea comes from applying Newton's second law to a small fluid element. That element feels forces from pressure differences, gravity, and changes in velocity. The resulting equation shows how fluid energy is shared. In the equation, P is pressure, ρ is fluid density, v is velocity, g is the acceleration due to gravity, and h is...

bernoulli's equation for flow normal to a streamline

bernoulli-s-equation-for-flow-normal-to-a-streamline

Pressure Changes Across Curved Streamlines

Bernoulli's equation for flow normal to a streamline describes how pressure changes across curved streamlines. When a fluid follows a curved path, the outer side of the curve experiences centrifugal force, which pushes the fluid outward. The pressure is therefore higher on the inner side, near the center of curvature, and lower farther out. The size of this pressure difference depends on the fluid's velocity and the radius of curvature. In flows with nearly straight streamlines, the pressure...

bernoulli's equation: problem solving

Venturi Meter Flow Rate from Pressure

A Venturi meter measures fluid flow rate in a pipeline by using pressure changes and Bernoulli's equation. In a sewage system, it can be used to determine wastewater flow rate by reading the pressure difference across the meter. The narrowed throat makes the fluid speed up, and that change in speed is linked to pressure drop. The first step is to find the cross-sectional areas of the pipe and the Venturi throat. These areas are needed to interpret the pressure difference shown on the pressure...

static, stagnation, dynamic and total pressure

Static pressure, dynamic pressure, stagnation pressure, and total pressure are key ideas in fluid dynamics. They are often explained with Bernoulli's equation. In that equation, p is static pressure, 1/2ρV^2 is dynamic pressure, γz is hydrostatic pressure or potential energy pressure, and pT is total pressure. For incompressible flow, the total pressure stays constant along a streamline. Static pressure is the pressure a fluid exerts when it is at rest, or when flowing fluid is brought to rest...

free jet

Liquid Speed from Reservoir Outlets

Free jets show how liquid moves after leaving a reservoir through an opening and flowing into the air without resistance. The jet speed is found with Bernoulli’s principle, and it depends on the height of liquid above the opening. This relationship assumes atmospheric pressure at both the reservoir surface and the jet exit. The liquid column’s height controls the speed at the nozzle because the fluid’s potential energy changes into kinetic energy during flow. As the liquid leaves the...

continuity equation

Fluid Flow and Area Changes

Fluid flow and area changes are linked by the continuity equation. For a steady flow of an incompressible fluid in a confined system, the mass flow rate stays constant. This idea is useful in nozzles, syringes, and pipes where the cross-sectional area changes. The mass flow rate is written as an equation that connects density, area, and velocity. For incompressible flow, the density stays the same, so the equation becomes simpler. When the area gets smaller, the fluid speed must increase. When...

energy line and hydraulic gradient line

Fluid Head Profiles in Pipes and Channels

Fluid head profiles in pipes and channels show how pressure, speed, and height change in a flowing fluid. These profiles come from Bernoulli's equation for steady, incompressible, inviscid flow. In that equation, total head includes pressure head, velocity head, and elevation head. The energy line (EL) shows the total head available in the flow. It sits above the datum and includes all three energy parts. Under ideal conditions, the EL stays horizontal because the total energy does not change...

design example: designing water slide

Water Slide Speed and Bernoulli's Principle

Water slide speed is controlled by Bernoulli's principle and the height of the slide. Engineers use these ideas to keep the ride exciting while making sure the water stays safe for riders. As water moves downhill, gravity makes it speed up. The water at the bottom depends on the height it starts from. A taller slide gives the water more potential energy at the top. That energy changes into kinetic energy as the water descends, so the flow becomes faster. Bernoulli's principle helps describe...

key terms and concepts

Learn how static, dynamic, stagnation, and total pressure relate to Bernoulli's equation and how a Pitot-static tube can be used to measure flow speed.

Pitot-Static Measurement in Bernoulli Flow | 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

Pitot-Static Measurement in Bernoulli Flow

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