I Does Pressure Multiplied by Volume and Volumetric Flow Rate Equal Force?

AI Thread Summary
The discussion centers on whether the equation combining pressure, volume, and volumetric flow rate can equate to force. Participants analyze the units involved, questioning the validity of the terms used in the equation. There is a concern about potential redundancy in the equation, particularly regarding the inclusion of both area and incremental volume. The conversation emphasizes the need to separate different physical effects, such as pressure and momentum change, rather than conflating them into a single term. Overall, the complexity of fluid dynamics requires careful consideration of each component's contribution to force.
FADFAD1
Does Pressure multiplied by volume multiplied by volumetric flow rate equal Force?
 
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FADFAD1 said:
Does Pressure multiplied by volume multiplied by volumetric flow rate equal Force?
Welcome to the PF. :smile:

What do the units work out as?
 
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berkeman said:
Welcome to the PF. :smile:

What do the units work out as?
N/m2 x m3 x m3/s so Nm4/s
 
FADFAD1 said:
x m3
Can you describe each term? It looks like you have an extra m^3 in there...?
 
the equation is pAdeltaL * dv/dt

so pressure times volume times change in length time volumetric flow rate
 
FADFAD1 said:
the equation is pAdeltaL * dv/dt

so pressure times volume times change in length time volumetric flow rate
The equation has pressure p.
Area A
Incremental length delta L
Incremental volume dv/dt

Are you not double-dipping? You have both area times incremental length and incremental volume?
 
In terms of a flowing fluid, there are multiple terms that contribute to force. One of them happens to be from pressure and looks like ##pA## (or rather ##\int p\;dA##). Your term has a bunch of extra stuff in it. My suspicion is that you are trying to combine too many physical effects into a single term rather than separating their contributions. Specifically, pressure effects and momentum change effects must be treated separately (though there are relationships between some of those variables).
 
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