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

ينص مبدأ برنولي على أن الضغط الكلي يظل ثابتا على طول خط انسيابي في نظام السوائل وهو مجموع ضغوط الطاقة الساكنة والديناميكية والكامنة.
الضغط الساكن هو القوة التي يمارسها السائل أثناء السكون ، والتي يتم ملاحظتها بشكل شائع في خطوط الأنابيب وأنظمة إمدادات المياه.
يعتمد ذلك على ارتفاع السائل وكثافته ويعمل بشكل عمودي على السطح عند ملامسته للسائل.
يرتبط الضغط الديناميكي بسرعة السائل ويمثل الطاقة الناتجة عن الحركة.
إنه أمر بالغ الأهمية في تصميم الأنظمة التي تنطوي على سوائل سريعة الحركة ، مثل تصريف مياه الأمطار أو قنوات الأنهار عالية السرعة.
يحدث ضغط الركود عندما يتم إحضار السائل إلى الراحة ، والجمع بين الضغوط الساكنة والديناميكية.
يتم قياسه عند نقاط الركود ، مثل أسطح السدود أو شفرات التوربينات ، حيث يتم تقليل سرعة السائل إلى الصفر.
يساعد فهم توازن الضغوط الساكنة والديناميكية والركود على إدارة تغيرات الضغط والطاقة في أنظمة السوائل.
يتم قياس هذه الضغوط باستخدام أجهزة مثل أنابيب Pitot-static ، وهي ضرورية لحسابات سرعة الهواء وتدفق السوائل في تطبيقات الهندسة المدنية المختلفة.

الضغط الاستاتيكي والضغط الراكد والضغط الديناميكي والضغط الكلي

<div style="direction:rtl">تعتبر مفاهيم الضغط الاستاتيكي والضغط الراكد والضغط الديناميكي والضغط الكلي مفاهيم أساسية في ديناميكا الموائع، وغالبًا ما يتم تفسيرها باستخدام معادلة برنولي:
<img alt="Equation 1" src="/files/ftp_upload/18036/18036_Equation_1.svg" style="text-align: center; height: 26px;">

هنا، p هو الضغط الاستاتيكي، و1/2⍴V2 هو الضغط الديناميكي، وyz هو الضغط الهيدروستاتيكي أو ضغط طاقة الوضع، وpT هو الضغط الكلي، وهو ثابت على طول خط الجريان للتدفقات الغير قابلة للانضغاط.

1. الضغط الاستاتيكي (p): هذا هو الضغط الذي يمارسه سائل في حالة سكون أو عندما يتم الابقاء على سائل متدفق في حالة سكون في اتجاه الحركة. يتم قياسه باستخدام مسبار يتم إدخاله في حيز التدفق أو بواسطة أنبوب بيزوميتر.

2. الضغط الديناميكي (1/2⍴V2): يعبر عن ارتفاع الضغط بسبب سرعة السائل. ويمكن تفسيره على أنه الطاقة الحركية لكل وحدة حجوم من السائل.
3. ضغط الركود (ps): هو مجموع الضغوط الساكنة والديناميكية عند نقطة الركود، والتي عندها تصبح سرعة السائل صفرًا:

<img alt="Equation 2" src="/files/ftp_upload/18036/18036_Equation_2.svg" style="text-align: center; height: 26px;">

4. الضغط الكلي (pT): هو مجموع الضغوط الساكنة والديناميكية والهيدروستاتيكية. على طول خط الجريان:

يقيس أنبوب بيتو الثابت ضغط الركود (ps) والضغط الاستاتيكي (p). يمكن تحديد سرعة السائل من خلال حساب الفرق:

<img alt="Equation 3" src="/files/ftp_upload/18036/18036_Equation_3.svg" style="text-align: center; height: 34px;">

يعد ضمان المحاذاة الدقيقة ووضع أنبوب بيتو الثابت أمرًا بالغ الأهمية في التطبيقات مثل قياس سرعة الهواء في الطيران. يمكن أن يؤدي عدم المحاذاة أو الانسداد إلى قراءات خاطئة، مما يؤثر على سلامة التشغيل.</div>

ينص مبدأ برنولي على أن الضغط الكلي يظل ثابتا على طول خط انسيابي في نظام السوائل وهو مجموع الثابت والديناميكي و ...

static-stagnation-dynamic-and-total-pressure

Education

JoVE Core

Civil Engineering

الهندسة المدنية

Unit 1

الوحدة الأولى

Fluid Dynamics

ديناميكا السوائل

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الرئيسية

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

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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...

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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 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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