Fluid flow through positive pressure gradient

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Discussion Overview

The discussion centers on the behavior of fluid flow through a positive pressure gradient, particularly in the context of Bernoulli's principle and its application in devices like diffusers and venturi meters. Participants explore the mechanics of fluid motion in regions where pressure increases, challenging the conventional understanding that flow occurs from high to low pressure.

Discussion Character

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

Main Points Raised

  • A participant questions how fluid can flow from a low pressure region to a high pressure region in a diffuser, given the common principle that flow occurs from high to low pressure.
  • Another participant suggests that fluid with kinetic energy will decelerate as it moves up the pressure gradient.
  • It is noted that fluid motion does not always align with negative pressure gradients; rather, it accelerates in that direction, and if fluid is already moving against the gradient, the pressure gradient will slow it down.
  • A participant proposes that the fluid entering the diffuser has sufficient momentum to overcome the positive pressure gradient, leading to flow, while kinetic energy is converted into pressure energy during this process.
  • One participant affirms that this concept aligns with Bernoulli's equation, indicating an energy balance at play.

Areas of Agreement / Disagreement

Participants express differing views on the mechanics of fluid flow in a positive pressure gradient, with some suggesting that momentum allows flow against the gradient while others emphasize the deceleration of fluid due to the pressure increase. The discussion remains unresolved regarding the implications of these ideas.

Contextual Notes

There are limitations in the assumptions made about fluid behavior in varying pressure gradients, and the discussion does not fully address the mathematical underpinnings of the claims made, particularly in relation to Bernoulli's equation.

Who May Find This Useful

This discussion may be useful for students learning about fluid dynamics, particularly those interested in Bernoulli's principle and its applications in engineering contexts such as flow measurement devices.

jacksimpson
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I am a student of 11th standard and being introduced to Bernoulli's principle made me wonder , how does flow takes place in positive pressure gradient (i.e. from low pressure region to high pressure region), in a diffuser or a diverging part of a venturi meter , since we know that flow always takes place from high pressure region to low pressure region ?.
it will be very kind of you to clear my confusion.
Thank you.
 
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The fluid having kinetic energy will decelerate as it climbs the pressure gradient.
 
Fluid motion does not always take place in the direction of negative pressure gradient; it always accelerates in that direction. If it already has motion against the pressure gradient, the gradient will serve to retard that motion, this the reason the velocity reduces through a diffuser.
 
yes sir i understand that. But can I say that the fluid at the diffuser inlet has enough momentum to overcome the positive pressure gradient and hence the flow. and as the flow occurs the kinetic energy is converted into pressure energy
 
Yes. That is essentially what Bernoulli's equation is telling you. It's an energy balance.
 

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