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

AI Thread Summary
The discussion centers on analyzing fluid flow in a pipe using Bernoulli's Equation and the Continuity Equation. Participants evaluate pressure and velocity relationships at various points in the pipe, with specific comparisons such as P1, P4 and v1, v2. There is a focus on understanding how gravity influences fluid velocity and pressure, with some confusion expressed about these effects. A warning is issued against providing direct answers to homework questions, emphasizing the importance of learning through problem-solving efforts. The conversation highlights the need for a deeper comprehension of fluid dynamics principles.
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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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