Fluid Flow in a Pipe: G-Greater, L-Less, E-Equal

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SUMMARY

The discussion focuses on fluid dynamics in a pipe, specifically analyzing pressure and velocity relationships using Bernoulli's Equation and the Continuity Equation. Key conclusions include that P1 is less than P4 due to increased velocity, and v1 is greater than 2v3 as a result of the Continuity Equation. The effects of gravity on pressure and velocity are also highlighted, with P4 being greater than P5 and P1 being greater than P2. The community emphasizes the importance of showing effort before receiving assistance on homework problems.

PREREQUISITES
  • Understanding of Bernoulli's Equation
  • Familiarity with the Continuity Equation
  • Basic knowledge of fluid dynamics concepts
  • Ability to analyze pressure and velocity relationships in fluid flow
NEXT STEPS
  • Study the implications of Bernoulli's Equation in various fluid flow scenarios
  • Explore the Continuity Equation in-depth, focusing on its applications in pipe flow
  • Research the effects of gravity on fluid dynamics in inclined pipes
  • Practice solving fluid dynamics problems involving pressure and velocity comparisons
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Students studying fluid dynamics, engineers working with fluid systems, and anyone seeking to understand the principles of pressure and velocity in pipe flow.

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Homework Statement


Use the picture as a guide. P is the pressure in the pipe, and vi is the speed of a non-viscous incompressible fluid at locations i = 1,2,3,4,5.(For each statement select G-Greater than, L-Less than, or E-Equal to).
prob07_Bernoulli.gif


A) P1 is ... P4
B) v1 is ... 2v3
C) P4 is ... P5
D) P1 is ... P2
E) v4 is ... v5
F) P3 is ... P4
G) v1 is ... v2

Homework Equations


Bernoulli's Equation p + .5ρv^2 + ρgy
Continuity Equation: A2*v2=A2*v2

The Attempt at a Solution


A) P1 < P4 because P1 has a higher velocity, so pressure must decrease to compensate.
B) v1 > 2v3, if the diameter is doubled, the velocity is quadrupled as per continuity equation
C) P4 > P5 due to gravity (ρgy)
D) P1 > P2 due to gravity
E) v4 > v5, if v4 has more pressure, it has higher velocity
F) P3 < P4 due to gravity
G) v1 > v2, since P1 has a higher pressure it has a higher velocity

Is my reasoning correct, or do I have something backwards? I guess my main confusion is what effect gravity has on velocity of flow?
 
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Those all look good to me except for E and G.

What does the Continuity Equation say about the velocities?
 
The answers to this question are as follows:

[Moderation Note: Complete solution removed. Hootenanny ][/color]

stevebo
 
Last edited by a moderator:
Stevebo said:
The answers to this question are as follows:...

Stevebo,

Please don't give direct answers to questions, that doesn't help people learn!

Please read the section on "Homework Help" here:
https://www.physicsforums.com/showthread.php?t=5374
In particular:
On helping with questions: Any and all assistance given to homework assignments or textbook style exercises should be given only after the questioner has shown some effort in solving the problem. If no attempt is made then the questioner should be asked to provide one before any assistance is given. Under no circumstances should complete solutions be provided to a questioner, whether or not an attempt has been made.
 

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