Bernoulli Eqn: Gauge vs Atm Pressure?

Click For Summary

Discussion Overview

The discussion revolves around the application of the Bernoulli equation, specifically addressing the treatment of gauge pressure versus atmospheric pressure in different parts of a fluid system. Participants explore the reasoning behind why certain pressures are considered gauge or absolute in specific contexts.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions why the absolute pressure in one part of the system is treated as atmospheric pressure (gauge pressure = 0) while another part requires both gauge and absolute pressure.
  • Another participant expresses confusion and requests an example to clarify the situation.
  • A participant notes that the problem states water exits into the atmosphere, implying that the gauge pressure at that point is 0.
  • There is mention of a solution that indicates the gauge pressure on one side is 0, which confuses some participants.

Areas of Agreement / Disagreement

Participants express confusion and seek clarification on the treatment of gauge and absolute pressures, indicating that there is no consensus on the reasoning behind the differing treatments in the application of the Bernoulli equation.

Contextual Notes

Participants have not fully resolved the assumptions regarding the definitions of gauge and absolute pressure in the context of the Bernoulli equation, leading to uncertainty in their discussions.

Bassel
Messages
9
Reaction score
0
why is when working with Bernoulli equation the absolute pressure that we are NOT looking for has a gauge pressure = 0 and only atmospheric pressure while the one we are looking for has both? is this a rule somehow ?
 
Physics news on Phys.org
Hi Bassel! :smile:

I don't understand. :redface:

Can you give an example? :smile:​
 
the last part of the problem

the last part of the problem by taking the absolute pressure of the right side equal to the atmospheric pressure only by taking the gauge pressure there as 0 while in the left part we are asked to find the gauge pressure. how come one has no gauge and the other has
 

Attachments

  • Untitled.png
    Untitled.png
    21.4 KB · Views: 515
thats the solution

that was the solution. the last part when we applied the equation and said the gauge pressure in the right side is 0 confused me
 

Attachments

  • Untitled2.png
    Untitled2.png
    11.6 KB · Views: 542
the question says that the water on the right goes out into the atmosphere

so it is at atmospheric pressure, ie the gauge pressure is 0 :smile:
 

Similar threads

Undergrad Fluid dynamics: drag coefficient and pressure at the stagnation point.
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Help Regarding Application of Bernoulli in a Boundary Layer
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Bernoulli to explain Magnus Effect
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad Exit velocity through a nozzle: Bernoulli vs. Experience
  • · Replies 7 ·
Replies
7
Views
4K
High School Problem with understanding deriving Torricelli's law
  • · Replies 14 ·
Replies
14
Views
2K
Undergrad Bernoull's Equation Derivation From Work - Energy Principle
  • · Replies 20 ·
Replies
20
Views
4K
Graduate Bernoulli’s equation for a rotating fluid
  • · Replies 4 ·
Replies
4
Views
3K
Graduate Bernoulli's equation, different streamlines, and wings
  • · Replies 4 ·
Replies
4
Views
2K
Graduate Does Fluid Dynamics Explain Pressure Gradients in a Frictionless Tube?
  • · Replies 48 ·
2
Replies
48
Views
6K
Undergrad Bernoulli's equation and the work energy theorem
  • · Replies 21 ·
Replies
21
Views
3K