What is Pipe flow: Definition and 73 Discussions

Pipe flow, a branch of hydraulics and fluid mechanics, is a type of liquid flow within a closed conduit (conduit in the sense of a means of containment). The other type of flow within a conduit is open channel flow.
These two types of flow are similar in many ways, but differ in one important aspect. Pipe flow does not have a free surface which is found in open-channel flow. Pipe flow, being confined within closed conduit, does not exert direct atmospheric pressure, but does exert hydraulic pressure on the conduit.
Not all flow within a closed conduit is considered pipe flow. Storm sewers are closed conduits but usually maintain a free surface and therefore are considered open-channel flow. The exception to this is when a storm sewer operates at full capacity, and then can become pipe flow.
Energy in pipe flow is expressed as head and is defined by the Bernoulli equation. In order to conceptualize head along the course of flow within a pipe, diagrams often contain a hydraulic grade line (HGL). Pipe flow is subject to frictional losses as defined by the Darcy-Weisbach formula.

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  1. T

    What Are the Flow Properties in the Entrance Region of a Pipe?

    Homework Statement Two dimensional, incompressible flow with constant properties in entry region of a horizontal pipe. Assume no swirl, neglect heat transfer. Determine governing equations. Question is: what are the properties of the entrance region of a pipe as far as flow is concerned...
  2. B

    What is the formula for finding pressure drop in pipe flow?

    Hi, Which equation should i be using to find the pressure drop across a channel. I know the length of the channel, the hydraulic diameter and the reynolds' number. Thank you
  3. R

    Turbulence Kinetic Energy in pipe flow

    What is the equation to estimate the turbulence kinetic energy per unit volume in pipe flow? Any information is appreciated. Thanks.
  4. W

    Computing Circulation in Pipe Flow using Velocity & Angular Direction

    I need to find the circulation for a flow in a pipe. I'm using the velocity in the angular direction (cylindrical coordinate system). Am I right in thinking that an ideal vortex is one where there is no vorticity? That would mean there is no circulation. It's strange, because the velocity is...
  5. 3

    Fluid Mechanis - Pipe Flow Velocity

    Homework Statement I'm looking for a formula that has velocity at a certain point in a pipe. I only have velocity and pipe diameter. The problem goes something like: A Tube with a 0.075 meter diameter has four drains equally spaced apart with a cap at the far end. Each of the four drain...
  6. J

    Deriving Half-Max Velocity in Pipe Flow

    Could someone help me with this. In pipe flow show that the average velocity is half of the maximum velocity. I have it written in my notes that this is true, but not how to derive it.
  7. B

    Transient inviscid incompressible pipe flow

    Hello I am trying to better understand transient fluid dynamics in pipes. First, I am attempting what I believe should be relatively simple problem. I have a constant area horizontal pipe partially filled with a stationary incompressible inviscid fluid. The part of the pipe that is filled is...
  8. P

    Perforated Pipe Flow with a closed end

    1. A hydroponic garden uses the 10 m long perforated pipe system to deliver water at 20ºC. The pipe is 5cm in diameter and contains a circular hole every 20 cm. A pump delivers water at 75 kPa (gage) at the entrance, while the other end of the pipe is closed. pressure near the closed end of the...
  9. O

    What Are Some Optimal Pipe Diameter Solutions for a Dual-Valve Fluid System?

    Hey guys, I am studying in heriot watt university Dubai. I would like to be a Fluids expert. I have been doing well in my course-works and my professor usually helps me around to get a few extra info. However recently due to a tight schedule he is unable to help me out. I have managed to...
  10. 5

    Fluid Mechanics - Split Pipe Flow Question (momentum and Bernoulli eqns)

    Hi, I am stuck on this question as I haven't encountered anything similar to it. Normally I have only dealt with pipe with one inlet/outlet. Homework Statement I am given a diagram of the pipe shown on the attachment (Sorry for the crude diagram). Hosted it while the attachment is "reviewed"...
  11. S

    How can the average velocity in laminar fully developed pipe flow be calculated?

    This question has been bugging for a while now. I have been trying to solve it, but not getting anywhere. Hopefully, you guys can be of some help. Here's the question: For laminar fully developed pipe flow, show the average velocity V = 0.5u(max). Any help will be greatly appreciated! Thanks!
  12. Y

    Calculating Water Tower's Drain Pipe Flow Rate

    A water tower, vented to the atmosphere, is drained by a pipe that extends to the ground. The top surface of the water in the tank is 13.3 m above the ground. If the valve in the drain pipe is closed, what is the absolute pressure in the drain pipe at ground level? 2.32×105 Pa If the valve...
  13. N

    Fluid - Determining pump power for pipe flow system

    Fluid - Determining pump power for pipeline with constant head gentlemen, i need some help to solve for part b as attached. The friction factor for pipe 1 & 2are 0.003106 and 0.003438 respectively and the Z value calculated is 9.997m of water. With a 20% increase in flow rate for the piping...
  14. 5

    Looking for pipe flow information in cubic feet per minute.

    Does anyone have a chart of what a straight pipe flows in cfm? Like 3 inch inside diam.? 4 inch? Etc? Thanks:)
  15. H

    Transition from pipe flow to open channel flow

    I'm working on a fluid flow problem that doesn't seem very complex but the solution is eluding me at the moment. Given a length of smooth tubing of known ID and roughness with water running through it, is it possible to predict at what velocity the flow will transition from "pipe" flow (fully...
  16. N

    How Can Unreacting Flow Dynamics Be Modeled in a Packed Bed Reactor?

    Hello all! This is a great site, congratulations! I think I need help for proceeding with my reaction engineering project. :rolleyes: Now the problem is this: I have a packed bed reactor whose dynamic modelling I am supposed to complete. At t = 0, there is still air in the reactor with...
  17. A

    Help with Pipe Flow: Tank Filling Proportion in 3 Hours

    A storage tank is replenished by an inflow pipe which can fill it in 8 hours.If the tank is initially full and the outflow pipe can empty it in 12 hours,what proportion of the tank is full after 3 hours duration?
  18. M

    Loss due to open channel to pipe flow transition

    Hi! I have the following equation for the entrance loss from an open channel to a pipe, but I'm not sure how it was derived: hloss = K*(V2^2 - V1^2)/2g I have always seen entrance losses as: K*(V^2)/2g, but why is the channel flow velocity considered in the equation above. Thanks...
  19. H

    Discovering Friction Loss in Pipe Flow with Blasius Formula and Fouling Effects

    Hi all! Let's say we are finding the friction loss for a pipe. And the reynolds number is low enough to use Blasius formula for the coefficient of pipe friction. What if I introduce some kind of fouling inside the pipe? Would the actual friction loss greater or smaller than the estimation...
  20. W

    Calculating Pressure and Flow in a Pipe System

    I have no idea how to solve this problem I know bernoulli's equaiton and the equation of continuity, but I don't know how to apply them to this problem...If someone could get me started I would be very appreciative. My final exam is monday and I fear this problem is going to be on the exam...
  21. A

    Fluids: calculate pressure loss due to turns in pipe flow

    Hi, I am trying to estimate the flow rate in a long pipe of rectangular cross section. The pipe is 100 m long and has twenty 180 degree turns. I have been able to calculate the pressure drip for a 100m straight pipe, but I have not been able to estimate the losses due to the turns. Is there...
  22. T

    Fluid Mechanics - Pipe Flow

    Hi there, I'm struggling with a question that I've been given regarding the force on a bend in a pipe, and I wondered if any of you guys could help me out with a few clues. The question is as follows: A contracting pipe bend turns water through 135° (In a horizontal plane) before discharging...
  23. S

    Parallel Pipe Flow: Potential Energy Drop

    Let us consider the following scenario. Water is pumped to high pressure, but the water then faces a fork in the pipe. Two pipes lead back to the pump: large pipe L and small pipe S. Since the water can flow through either pipe, the pipes are said to be in parallel. Since this is so, the overall...
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