Preesure changes in fliud movement

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Discussion Overview

The discussion revolves around the calculation of pressure changes and lifting forces in a system where a grooved surface rotates while a smooth surface remains stationary, with a liquid present in the grooves. The focus is on understanding the fluid dynamics involved, particularly in relation to the Bernoulli equation and potential effects such as surface tension.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant describes a scenario involving a rotating grooved surface and a stationary smooth surface, seeking to calculate the pressure differences and lifting forces generated by the fluid movement.
  • Another participant seeks clarification on whether the grooved surface is stationary or rotating, indicating a potential misunderstanding of the setup.
  • A participant questions the applicability of the Bernoulli equation to this situation, suggesting a need for further exploration of fluid dynamics principles.
  • One participant expresses uncertainty about their ability to contribute, suggesting that surface tension effects of the lubricant might play a role, but defers to more knowledgeable individuals for a definitive answer.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the applicability of the Bernoulli equation or the specific mechanisms at play. Multiple viewpoints and uncertainties remain regarding the fluid dynamics involved.

Contextual Notes

There are unresolved assumptions regarding the specific conditions of the fluid movement and the definitions of the forces at play. The discussion does not clarify the mathematical steps necessary for calculating the pressure differences or lifting forces.

Who May Find This Useful

Individuals interested in fluid dynamics, engineering applications involving rotating systems, and those studying the effects of pressure changes in fluids may find this discussion relevant.

superb
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Hope you guys can help me in solving this problem...

There one grooved surface seal the another smooth surface from bottom ...
inside the grooved surface there will be a liquid... this grooved surface will rotate at certain speed , while the smooth surface on the bottom will remain stationary.

The problem is the pressure changes result from the movement of the fluid inside the grooves will lift the grooved surface... how to calculate this pressure different and lifting force ?


p/s what i know, the high speed fluid will result the low pressure... how come there lifting force?
 
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Welcome to PF, Superb.
I'm having a bit of trouble understanding your question. Do you mean that you have a stationary seal with oiled grooves in the interior surface within which the shaft rotates?
 
yes, that's what i mean


could you help me... can i use the Bernoulli equation for this application?
 
I'm afraid that I can't help you, pal. I never finished high-school. My first thought is that it would be a surface-tension effect of the lubricant. You really have to wait for a real scientist to answer you, though.
 

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