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

Bernoulli's principle states that the total pressure remains constant along a streamline in a fluid system and is the sum of static, dynamic, and potential energy pressures.
Static pressure is the force exerted by a fluid at rest, commonly observed in pipelines and water supply systems.
It depends on the fluid's height and density and acts perpendicular to the surface in contact with the fluid.
Dynamic pressure is related to the fluid's velocity and represents the energy due to motion.
It is crucial in designing systems involving fast-moving fluids, such as stormwater drainage or high-velocity river channels.
Stagnation pressure occurs when the fluid is brought to rest, combining static and dynamic pressures.
It is measured at stagnation points, like dam surfaces or turbine blades, where the fluid's velocity is reduced to zero.
Understanding the balance of static, dynamic, and stagnation pressures helps manage pressure changes and energy in fluid systems.
These pressures are measured using devices like Pitot-static tubes, critical for airspeed and fluid flow calculations in various civil engineering applications.

static, stagnation, dynamic and total pressure

The concept of static, stagnation, dynamic, and total pressure is fundamental in fluid dynamics, often explained using Bernoulli's equation:
<img alt='Equation 1' src='/files/ftp_upload/18036/18036_Equation_1.svg' style='text-align: center; height: 26px;' />
Here, p is static pressure,1/2&#9076;V2 is dynamic pressure, &#947;z is hydrostatic pressure or potential energy pressure, and pT is total pressure, constant along a streamline for incompressible flows.
1. Static Pressure (p): This is the pressure exerted by a fluid at rest or as if flowing fluid is brought to rest in the direction of motion. It is measured using a probe inserted into the flow or by a piezometer tube.
2. Dynamic Pressure (1/2&#9076;V2): It represents the pressure rise due to the fluid's velocity. It can be interpreted as the kinetic energy per unit volume of the fluid.
3. Stagnation Pressure (ps): It is the sum of static and dynamic pressures at a stagnation point, where the velocity of the fluid becomes zero:
<img alt='Equation 2' src='/files/ftp_upload/18036/18036_Equation_2.svg' style='text-align: center; height: 26px;' />
4. Total Pressure (pT): This is the sum of static, dynamic, and hydrostatic pressures. Along a streamline:
A Pitot-static tube measures stagnation pressure (ps) and static pressure (p). By calculating the difference, the velocity of the fluid can be determined:
<img alt='Equation 3' src='/files/ftp_upload/18036/18036_Equation_3.svg' style='text-align: center; height: 34px;' />
In applications, such as measuring airspeed in aviation, ensuring accurate alignment and placement of the Pitot-static tube is critical. Misalignment or blockage can lead to erroneous readings, impacting operational safety.

Static, Stagnation, Dynamic and Total Pressure

Bernoulli's principle states that the total pressure remains constant along a streamline in a fluid system and is the sum of static, dynamic, and ...

static-stagnation-dynamic-and-total-pressure

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JoVE Core

Civil Engineering

Unit 1

Fluid Dynamics

KEY TERMS AND CONCEPTS

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

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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 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...

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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...

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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...

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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 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.

Pitot-Static Measurement in Bernoulli Flow

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