What is Static pressure: Definition and 52 Discussions

In fluid mechanics the term static pressure has several uses:

In the design and operation of aircraft, static pressure is the air pressure in the aircraft's static pressure system.
In fluid dynamics, many authors use the term static pressure in preference to just pressure to avoid ambiguity. Often however, the word ‘static’ may be dropped and in that usage pressure is the same as static pressure at a nominated point in a fluid.
The term static pressure is also used by some authors in fluid statics.

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  1. A

    B What actually is static pressure?

    I’ve been confused about the term static pressure for quite some time. Different sources use very different definitions. From the problems perspective, it’s usually some external pressure. For example we are having a pool with tiny hole on the bottom which makes water level decrease and it flows...
  2. S

    Hospital Air Handler, Discharge Airflow vs. Static Pressure

    We have a new AHU installed for a Compounding Pharmacy. The unit has two return fans and two supply fans. They are installed in parallel and are powered by VFDs. In the event of one fan failing, the other fan is supposed to speed up to maintain static pressure in the clean environment. This...
  3. PaxFinnica96

    Engineering Fluid Dynamics: Proof of the Static Pressure Head equation

    I am trying to mathematically prove the Static Pressure Head equation: H = p/ρg How can I prove this equation and thus determine the nature of the relationship between these variables?
  4. T

    Low pressure, high velocity flow vs static pressure

    In this scenario, we have a compressible flow at 0.99 barA pressure and flowing at 300 m/s velocity and is released into 1 barA pressure. Point is, whether the flow can be released at 1 barA or not at the release pressure is higher than the pressure of the compressible fluid inside the tube. And...
  5. J

    How calculate lift/drag using static pressure taps in wind tunnel test?

    An airfoil section in a wind tunnel has many static ports/holes/taps on its upper and lower surface. These static ports can only read static pressure which acts perpendicularly to the local airfoil surface. In place A are static ports that read a pressure value of relative -100 Pa . This...
  6. F

    Why is static pressure called "static"?

    Hello, I am still perplexed on why the pressure term ##p## in Bernoulli and Euler equations is called "static", even if the fluid is flowing (moving). Are there historical or other specific reasons? In hydrostastics, the pressure at a certain depth is called hydrostatic which makes sense since...
  7. G

    HVAC How to know if a blower will be able to overcome system resistance?

    The rectangular chamber contains inclined perforated plates through which the air passes. At the top there is a blower and at the front as well as back bottom there are openings for air inlet. How do I calculate system resistance and know if a certain blower will be able to overcome it?
  8. F

    Static pressure in a water pipe system

    I have a problem where I want to find out the static pressure over a city in a water pipe system. As I know the elevations over the city I was first thinking of just using p = rho * g * h, but this should only apply if the pipe system were under water (if I use the density of water at least). So...
  9. B

    Dynamic/Static pressure -- High speed railways

    I am currently doing a research project in the attenuation of pressure waves. With an focus on dealing with sonic booms the are generated from high speed train tunnels. my experiments involved pressurizing a cylinder then using a rapid release valve allowing the air to escape along a pipe. I...
  10. S

    Static pressure and hydrostatic pressure

    Hello can someone explain the difference between static and hydrostatic pressure in terms of a water in a glass
  11. longz

    Sizing fan static pressure to open a cover

    Hi all great PF members, Can anyone help me to sizing fan static pressure strong enough to open a metal cover an angle 15 degree at the end of the duct (20m in length with few 90 degree bends), I'm really not good at math so any help are greatly appreciated. Please refer to sketch attached for...
  12. F

    Calculate theoretical static pressure drop in moving fluid

    Hi folks, I have a pressure sensor working with arduino to measure depth. I want to calculate what I should see as a change in pressure if I move the tube horizontally under the surface of the water, keeping the tube opening parallel to the flow. I have calculated the dynamic pressure but...
  13. A

    Pitot Tubes and Static Pressure

    Hey so I am learning physics on Khan academy and they had a video on Pitot tubes: https://www.khanacademy.org/science/physics/fluids/fluid-dynamics/v/venturi-effect-and-pitot-tubes I had a question. I understand that the lower part of the pitot tube in the video is measuring the pressure...
  14. C

    Can static pressure be controlled in a pipe without adjusting the flow rate?

    Hi everyone, Is there any mechanism/method/device to control static pressure? Noting that, total pressure = static + dynamic pressure. The scenario I am thinking is just water flowing through a pipe (assume incompressible), and I want to control the static pressure at two points along the pipe...
  15. morrobay

    Static Pressure and Dynamic Pressure to Atmospheres

    Homework Statement [/B] Calculate the dynamic water pressure at submarine outfall from a pipe 2m diameter , 500 m length at depth of 52 meters with velocity 41m/sec. Pipe is at 100 relative to x axis. Water is released from reservoir on shore at sea level. Then calculate the static water...
  16. F

    Fluid Dynamics: Static pressure in compressible Liquids

    Homework Statement [/B] "Derive a relation between the static pressure P at a point and its depth y from the free surface of the liquid. Given the surface density of liquid is ρο, and compressibility of the liquid is k." Homework Equations ##ρ(P) = ρ_οe^{kP}## ##dP = ρg dy## The Attempt at a...
  17. can12345

    Static Pressure in Transmission Lines - Understanding the Differences

    Homework Statement Is there any difference if I measure static pressure value from the down side of the pipe or up side of the pipe? I am getting an error just small as 300 pascal when I do zero measurement. Here I draw the system also. The diameter of pipe is 10 cm. What could be the possible...
  18. I

    Static Pressure in relation to CFM

    Hey all, I’ve scoured the internet in search of an answer to no avail, so it’s time to ask the experts!My background is more Chemistry and Biology, not Physics, or specifically fluid dynamics, so bear with me! Also, this is a little long, so I will do my best to make it easy to follow.The...
  19. T

    Surge Pressure Stagnation Pressure Static Pressure Bernoulli

    I have trouble understanding why Stagnation Pressure equals Total Pressure when we apply Bernoullis theorem to a constriction. Two different scenarios Scenario 1.A pipe has pressure p_1 , its flow is velocity v_1 and a diameter a_1 ,it has no restriction along its length. Total Pressure Tp_1...
  20. A

    Static Pressure along bounded channel

    Homework Statement [/B] Note: There is NO z variation, everything is horizontal (imagine looking down at streamlines)Homework Equations Bernoulli's Equation along streamline: P + 1/2*ρ*V2 + ρ*g*h = Constant ... (1) Bernoulli's Equation normal to streamline: P + ρ*V2*(1/R) + ρ*g*h =...
  21. umair20

    Static Pressure: Exploring Its Development & Forces

    In many books & articles that I have read; static pressure has been defined as pressure of a fluid at rest. In some articles, it is said to be the pressure which is applied against frictional forces in a fluid. But I want to know how a fluid develops static pressure & what is basic force in this...
  22. C

    Static pressure in Air Handling Unit

    what will happen if static pressure in supply duct is higher than the fan compartment in AHU?? or vice-versa thanks
  23. Y

    Static pressure inside an air conditioner's capillar

    Let's a system be as follows (with approximate but, still, real numbers). Compressed refrigerant gas get condensed in a condenser and as liquid with +/- 15 B SP enters a capillary (a "metering device"). It exits the capillary at high speed and enters the pipe leading to the evaporator having...
  24. A

    Manometry to determine static pressure in a pipe.

    Please see attached for question and attempted solution, Im pretty sure this is correct, can anybody confirm? Regards, A
  25. Y

    Static Pressure in Gravity-Fed Water System: Analyzing Real-World Problem

    I have a somewhat theoretical question based on a real world problem regarding a gravity-fed domestic water system: I have a very large tank (~10,000 gal) at 300' elevation supplying water to a piping system consisting of a 6" line coming down from the tank to a tee at 100' elevation. Branch...
  26. K

    The minimum cost of converting static pressure into dynamic pressure

    Can static pressure be induced to becoming dynamic pressure through the use of "right-angle forces" with respect to particle velocities? I imagine that one could accomplish this with an ionized gas and a magnetic field. This would reduce the amount of work that is need to accelerate the gas...
  27. M

    Static pressure and airflow at reduced fan speeds

    This is probably a stupid question but I've been going around in circles for a while now and have gotten myself completely confused. I have a fan and a pump, with performance charts (static pressure vs. air flow) for both. I need to try and determine flow rates for each device when run at...
  28. R

    How does dynamic pressure affect static pressure?

    I have attached another diagram, and in the diagram I show a round piston with a 1 sq ft surface area pushing water through the pipe out into to open atmosphere at 14.7 psi at a constant velocity of 75 ft/sec. There is a vacuum behind the piston, and I have calculated a 37.9 psi dynamic pressure...
  29. H

    Finding static pressure of rotor

    I've been reading a helicopter aerodynamics book and found that you can only find the induced velocity by using the Momentum theory and Bernoulli's Principle. If I don't know the thrust the rotor is generating, then I have to find the induced velocity of the rotor, where Atmospheric pressure =...
  30. R

    How Do You Calculate Static Pressure on Hypersonic Vehicles?

    I'm confused about finding the static pressure on a surface of a hypersonic vehicle. I know the inclination angle of surface 1 relative to the horizontal and I know all the aerodynamic characteristics of stage 1. With a calorically perfect gas assumption, gamma=1.4. I'm getting a little...
  31. H

    Simple Static Pressure problem, with units

    Homework Statement Hi I'm having trouble solving this physics problem if anyone can help it would be greatly appreciated ! Static pressure problem: A bathtub contains water to a depth of 20 inches. Determine the pressure at the bottom of the bathtub in both [psia] and [psig] (a being...
  32. H

    Simple Static Pressure problem, with units

    Homework Statement Hi I'm having trouble solving this physics problem if anyone can help it would be greatly appreciated ! Static pressure problem: A bathtub contains water to a depth of 20 inches. Determine the pressure at the bottom of the bathtub in both [psia] and [psig] (a being...
  33. J

    Static Pressure Variation on Vehicles: Impact on Aerodynamics

    hi, this is the first time i am using this website and have found it very informative ao far.. so i am working on this assignment and have got stuck on this question. the query is .. why does static pressure vary on the surface of vehicles and how does it affect the aerodynamic...
  34. R

    Static pressure in Compressor, Burner, Turbine

    I posted a question about this a couple days ago but I have since solved for the total temperatures in the compressor, burner, and turbine. My question is this. How do I calculate the static pressure in the compressor, burner, and turbine when i know the following data at each station...
  35. M

    How to measure static pressure

    have a manometer. i want to measure the static pressure for calculation of axial flow fan efficiency. please tell me how would i do it. Regards.
  36. Z

    Finding mass flow rate and static pressure

    Homework Statement I was asked to find the mass flow rate and static pressure Homework Equations Bernoulli's equation The Attempt at a Solution I simply assumed that the area of the water jet hitting the vane is equals to the total area of water leaving the vane. I'm not sure if my...
  37. S

    Calculating Static Pressure at Various Points in a Tank

    Homework Statement what is the static pressure (pt-139) at the top of the tank answer in psi Homework Equations P=H" * S.G. (I think) The Attempt at a Solution I took the total height of the tank it's 18 feet (216 inches) and multiplyed it by 1.44 and I got 406.08 psi I'm...
  38. H

    Static pressure decreases pump work

    Hey just wanted to know the theory behind this. If i have a open reservoir say 20 ft above a pump and i want to pump the water that flowing down on the suction side to a reservoir on the discharge side 80 ft above, the static pressure from the suction reservoir should decrease the pumps work,but...
  39. C

    Calculating Static Pressure Through Duct Network

    Hi, My name is CK and I have question on calculating static pressure through a ducting network. Some context: The ducting network services 360 identicle components. This is achieved by dividing a main duct into 4 branches, each servicing approximately 90 components. There is a desired...
  40. G

    Very Confused Static Pressure?

    Hi, I am trying to calculate as best but simply as i can the (approx) thrust from a propeller.. and my research shows i have to calculate: prop velocity(pv) = pitch * rpm with pv i can then use Bernoulli's equation to calulate the pressure and multiply it by the propeller surface area...
  41. P

    Static pressure in round pipe bends do what?

    In the controversial and well misunderstood Bourdon gauge phenomenon, I found by experiments that a flat or oval shaped bourdon tube will increase in volume significantly as the tube straightens. I filled the gauge tube with water and moved the tube with my hands. As I straightened the tube...
  42. M

    Total pressure and Static Pressure and V

    Confusion... I'm probably being stupid but... Aerofoil in a wind tunnel... there are lots of pressure tappings including Pt and Ps (static and total pressure freestream) these are currently in mm on a manometer.. my Pt is 11.4mm and Ps is 16.8mm.. (SG=0.8) 1st question: Should total...
  43. D

    Confused with static pressure and total pressure and Bernoulli's eq

    hi all, am a confused-being after trying to solve this really simple question.. somewhere somehow my concepts are just not right ): Consider an airplane flying with a velocity of 60m/s at a standard altitude of 3km. At a point on the wing, the airflow velocity is 70m/s. Calculate the...
  44. D

    Relationship between static pressure and CFM

    I am wanting to create a moderate amount of suction with a blower fan and I am trying to figure out the relationship between static pressure and airflow measured in CFM. Does higher CFM necessarily give you greater static pressure? I'm thinking I need between 150 to 200 CFM to get around 1...
  45. W

    Static pressure vs. dynamic pressure

    I am having trouble relating the two quantities of dynamics and static pressure in: 1/2p*v^2 + p = constant, bernoullis equation, to corresponding physical descriptions. In what way do the air molecules act to create both dynamic and static pressure, respectivley? As far as i know, dynamic...
  46. G

    How Does Height Affect Static Pressure in a Hydroelectric System?

    A hydroelectric power station is supplied with water from a reservoir. A pipeline connects the reservoir to the turbine hall. The flow of water through the pipeline is controlled by a valve which is located 500 metres below the surface of the water in the reservoir. The lower end of the...
  47. G

    Static pressure in ducts and vessel

    If air is venting thru a 10" duct and there is a static pressure drop of 2” water column for every 100’ of length at 2000 cfm and the duct opens to a 1000 cubic feet airtight vessel and exits through another 100’ of 10” duct how can you find the pressure drop for the tank alone?
  48. I

    Calculating Water Velocity with Static Pressure

    with static pressure(water in a tube or column) not moving. Is there an equation I can use to determine the velocity of the water by the pressure of the water in the tube or column.
  49. Cyrus

    Static Pressure Poorly Described by Texts

    I just finished reading the theory of static pressure in relation to the bernoulli equation: P + \frac{1}{2} \rho V^2 + \gamma z = Const Here, we have three terms and a corresponding relationship. P- is the static or thermodynamic pressure measurment of the fluid. It is the measurment...
  50. kach22i

    Hovercraft Thrust - Velocity verses Static Pressure

    I am trying to get my mind around concept of Velocity verses Static Pressure in simple terms. Using a hovercraft as our topic model, I understand that high static pressure is desired for the lift system, and high velocity for the thrust system. Therefore it's nice two have two systems one...