Hydraulic pressure dropping bottle

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    Hydraulic Pressure
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Discussion Overview

The discussion revolves around calculating the hydraulic pressure at the bottom of a bottle filled with liquid at the moment of impact after falling a certain distance. Participants explore the relationship between the force of impact and the resulting pressure exerted on the liquid and the bottom of the bottle, considering principles of fluid mechanics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the force of impact can be used to determine the hydraulic pressure at the bottom of the bottle, suggesting that estimating pressure could involve dividing the force by the area of the bottom of the bottle.
  • Another participant notes that the total impact force at the point of contact includes both the mass of the bottle and the liquid, and discusses how the liquid's energy is distributed upon impact.
  • Several participants reference Pascal's principle to relate the pressure at the top of the fluid to the pressure at the bottom, but express uncertainty about the relevance of the impact force in this calculation.
  • One participant suggests that the hydrostatic head pressure may be negligible compared to the impact pressure, and proposes ignoring certain pressures in the calculations.

Areas of Agreement / Disagreement

Participants express uncertainty about the relationship between the impact force and the hydraulic pressure at the bottom of the bottle. There are multiple competing views on how to approach the calculation, and no consensus is reached regarding the relevance of the impact force.

Contextual Notes

Participants highlight assumptions regarding the distribution of force and the effects of hydrostatic pressure, but these assumptions remain unresolved within the discussion.

onebad1968
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I am attempting to calculate the pressure at the bottom of a bottle at the moment of impact. I have calculated the force of impact ,but now I am unsure if this will be the same force (approx) applied to the top of the liquid to determine the hydraulic pressure at the bottom of the bottle.
In other words I need to find the hydraulic pressure exerted in a bottle, ( a full bottle that has fallen a certain distance).
If i have a bottle full of liquid of given mass falling a given distance.I can calculate the force at which it impacts. But does this help me find the answer to the above question?
 
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onebad1968 said:
I am attempting to calculate the pressure at the bottom of a bottle at the moment of impact. I have calculated the force of impact ,but now I am unsure if this will be the same force (approx) applied to the top of the liquid to determine the hydraulic pressure at the bottom of the bottle.
In other words I need to find the hydraulic pressure exerted in a bottle, ( a full bottle that has fallen a certain distance).
If i have a bottle full of liquid of given mass falling a given distance.I can calculate the force at which it impacts. But does this help me find the answer to the above question?

I suppose you could estimate it by simply dividing the force by the area of the bottom of the bottle. This makes the assumption that the force is distributed evenly across the bottom and the fluid is in contact with the bottom of the bottle at impact.

CS
 
It would seem to me that the sum of both masses, (bottle and liquid) will make up the total impact at point of outside contact. The liquid inside will gain energy in the fall, but being a liquid will spread it's energy at impact to the inside bottom and all around the inside walls of the bottle, also the gas portion above the liquid would receive some of the energy through compression.

Just don't ask me to do any math:biggrin:

Ron
 
According to pascals principle.. The pressure applied to the top of the fluid can be calculated by using... (P1 being a force pushing down on the top of the liquid)

p1= Force1/area1... The pressure on the bottom of the bottle p2=p1+static fluid pressure.. and finally the force on the bottom of the bottle F2 = P2 A2. so I still don't know if the calculation of the force at which the bottle hits is relevant to calculating the above or is there another way to do this.
 
onebad1968 said:
According to pascals principle.. The pressure applied to the top of the fluid can be calculated by using... (P1 being a force pushing down on the top of the liquid)

p1= Force1/area1... The pressure on the bottom of the bottle p2=p1+static fluid pressure.. and finally the force on the bottom of the bottle F2 = P2 A2. so I still don't know if the calculation of the force at which the bottle hits is relevant to calculating the above or is there another way to do this.

Draw a FBD and sum the forces. Then calculated the pressure. There will be a small hydrostatic head pressure plus whatever pressure is generated by the impact force. The hydrostatic head is probably negligible compared to the equivalent impact pressure so you can probably just ignore it. P1 is on the top of the bottle (atmospheric) and on the bottom so it cancels out...ignore it too.

CS
 

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