Find the speed of fluid using bernoulli

Click For Summary
SUMMARY

The discussion focuses on applying Bernoulli's equation to determine the velocity of fluid in a pipe. The user correctly simplifies the equation by assuming atmospheric pressure at both ends and setting the initial velocity and height to zero, leading to the conclusion that the fluid velocity can be expressed as v = √(2gh). The user confirms their understanding of the concepts involved, including the equation of continuity, which justifies the assumption of zero velocity at the water surface due to its larger cross-sectional area compared to the pipe.

PREREQUISITES
  • Understanding of Bernoulli's equation
  • Knowledge of fluid dynamics principles
  • Familiarity with the concept of pressure in open systems
  • Basic algebra for manipulating equations
NEXT STEPS
  • Study the derivation of Bernoulli's equation in fluid mechanics
  • Learn about the equation of continuity and its applications
  • Explore real-world applications of Bernoulli's principle in engineering
  • Investigate the effects of viscosity on fluid flow
USEFUL FOR

This discussion is beneficial for students studying fluid dynamics, engineers working with fluid systems, and anyone seeking to understand the practical applications of Bernoulli's equation in real-world scenarios.

songoku
Messages
2,508
Reaction score
402

Homework Statement


untitled-7.jpg


Find v


Homework Equations


Bernoulli


The Attempt at a Solution


Here's what I've done

I took the surface of water as first reference and the right-end of the pipe as second reference, so:

P1 + 1/2 ρV12 + ρgh1 = P2 + 1/2 ρV22 + ρgh2

P1 = P2 = Patm and I assumed v1 = 0 and h1 = 0, then the equation became:
0 = 1/2 ρV2 - ρgh
v = √(2gh) ---> ta daa, I'm finished with degree of confidence 0.5 % that my answer is correct.

Do I get it right? Thanks
 
Physics news on Phys.org
It is 100% correct.

However to build up your confidence let's just clear up how we got here.

After applying the equations, we realized two things.Pressure at surface and Pressure at exit are same as they are open to atmosphere.

Then we made velocity zero.
That was using equation of continuity as surface area of water is much greater than that of pipe.
 
Ah I get it. Thanks for the help :smile:
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 13 ·
Replies
13
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
Replies
7
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
629
Replies
2
Views
4K
Replies
25
Views
5K