Increase Velocity of Fluid: Less Pressure?

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Discussion Overview

The discussion centers around the relationship between fluid velocity and pressure, specifically addressing why an increase in fluid velocity is associated with a decrease in pressure. The scope includes theoretical concepts related to fluid dynamics, particularly the continuity equation and Bernoulli's principle.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants suggest that the continuity equation explains the relationship, asserting that the mass of a moving fluid remains constant, leading to equal volume flow rates.
  • Others reference Bernoulli's equation, indicating that as fluid velocity increases in a narrower cross-section, pressure must decrease to maintain the equation's balance.
  • A participant introduces a speculative idea about molecular behavior, proposing that a constriction in the flow acts as a "velocity filter," affecting the acceleration of molecules.
  • Another participant recalls that the left side of Bernoulli's equation remains constant, implying that pressure must vary inversely with velocity.

Areas of Agreement / Disagreement

Participants express differing views on the mechanisms behind the observed relationship between fluid velocity and pressure, with no consensus reached on the explanations provided.

Contextual Notes

Some claims rely on specific interpretations of fluid dynamics principles, and there may be assumptions about ideal conditions that are not explicitly stated. The discussion does not resolve the underlying complexities of the concepts involved.

Who May Find This Useful

This discussion may be of interest to students and professionals in physics, engineering, and fluid dynamics, particularly those exploring the principles of fluid behavior and pressure dynamics.

bluejay27
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Why is there less pressure if the velocity of the fluid is increased?
 
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I obtained the answer! It deals with the continuity equation, where the mass of a moving fluid does not change as it flows. Thus, the volume flow rate has to be equal at all times.
 
Nevermind that still does not answer my question. Why is there less pressure when the velocity of fluid is increased?
 
bluejay27 said:
Nevermind that still does not answer my question. Why is there less pressure when the velocity of fluid is increased?
You can look at the Bernoulli equation! Since, the left side of its equation is constant, the right side must equal to each other. If there is a smaller cross-section, there will be a higher speed and in order to make the equation equivalent to the left side of the equation, the P at the right side of the equation must decrease.
 
bluejay27 said:
I obtained the answer! It deals with the continuity equation, where the mass of a moving fluid does not change as it flows. Thus, the volume flow rate has to be equal at all times.
That's one of two parts: that's conservation of mass (flow). The other is conservation of energy.
 
ive often wondered what causes the molecules to accelerate. some say that the neck down is a kind of "velocity filter" and allows the high speed vibrations of the molecules to prioritize the ones pointed in the right direction, through.
 
Been a while since I took physics, but I believe that because the left side of the Bernoulli equation stays constant the pressure must vary proportionally with the velocity. So as the water speeds up, it must exert a lower pressure on its surroundings.
 

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