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

Il principio di Bernoulli afferma che la pressione totale rimane costante lungo una linea di flusso in un sistema di fluidi ed è la somma delle pressioni statiche, dinamiche e di energia potenziale.
La pressione statica è la forza esercitata da un fluido a riposo, comunemente osservata nelle condutture e nei sistemi di approvvigionamento idrico.
Dipende dall'altezza e dalla densità del fluido e agisce perpendicolarmente alla superficie a contatto con il fluido.
La pressione dinamica è correlata alla velocità del fluido e rappresenta l'energia dovuta al movimento.
È fondamentale nella progettazione di sistemi che coinvolgono fluidi in rapido movimento, come il drenaggio delle acque piovane o i canali fluviali ad alta velocità.
La pressione di ristagno si verifica quando il fluido viene messo a riposo, combinando pressioni statiche e dinamiche.
Viene misurata nei punti di ristagno, come le superfici delle dighe o le pale delle turbine, dove la velocità del fluido è ridotta a zero.
Comprendere l'equilibrio tra pressioni statiche, dinamiche e di ristagno aiuta a gestire le variazioni di pressione e l'energia nei sistemi di fluidi.
Queste pressioni vengono misurate utilizzando dispositivi come i tubi statici Pitot, fondamentali per i calcoli della velocità dell'aria e del flusso dei fluidi in varie applicazioni di ingegneria civile.

pressione statica, di ristagno, dinamica e totale

Il concetti di pressione statica, di ristagno, dinamica e totale sono fondamentali nella dinamica dei fluidi, e sono spesso spiegati utilizzando l'equazione di Bernoulli:

<img alt="Equation 1" src="/files/ftp_upload/18036/18036_Equation_1.svg" style="text-align: center; height: 26px;">

Qui, p è la pressione statica, 1/2⍴V^2 è la pressione dinamica, γz è la pressione idrostatica o pressione di energia potenziale e p_T è la pressione totale, costante lungo una linea di flusso per flussi incomprimibili.

<ol style="display: flex; flex-direction: column; gap: 10px;">
<li>Pressione statica (p): questa è la pressione esercitata da un fluido a riposo o come se il fluido che scorre, fosse portato a riposo nella direzione del movimento. Viene misurata utilizzando una sonda inserita nel flusso o da un tubo piezometrico.</li>

<li>Pressione dinamica (1/2⍴V^2): rappresenta l'aumento di pressione, dovuto alla velocità del fluido. Può essere interpretata come l'energia cinetica per unità di volume del fluido.</li>

<li>Pressione di ristagno (p_s): è la somma delle pressioni statica e dinamica in un punto di stagnazione, dove la velocità del fluido diventa zero:</li>

<img alt="Equation 2" src="/files/ftp_upload/18036/18036_Equation_2.svg" style="text-align: center; height: 26px;">

<li>Pressione totale (p_T): è la somma delle pressioni statica, dinamica e idrostatica. Lungo una linea di flusso:</li>
 </ol>

Un tubo Pitot-statico misura la pressione di ristagno (p_s) e la pressione statica (p). Calcolando la differenza, è possibile determinare la velocità del fluido:

<img alt="Equation 3" src="/files/ftp_upload/18036/18036_Equation_3.svg" style="text-align: center; height: 34px;">

In applicazioni come la misurazione della velocità dell'aria in aviazione, è fondamentale garantire un allineamento e un posizionamento accurati del tubo Pitot-statico. Un disallineamento o un blocco, possono portare a letture errate, con un relativo impatto sulla sicurezza operativa.

Pressione Statica, di Ristagno, Dinamica e Totale

Il principio di Bernoulli afferma che la pressione totale rimane costante lungo una linea di flusso in un sistema di fluidi ed è la somma di statica, dinamica e ...

static-stagnation-dynamic-and-total-pressure

Education

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JoVE Core

Civil Engineering

Ingegneria Civile

Unit 1

Unità 1

Fluid Dynamics

Dinamica dei fluidi

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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...

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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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