Fluid flow through a pipe - Conservation of mass and/or momentum?

AI Thread Summary
The discussion centers on the application of conservation of mass and momentum in fluid flow through a nozzle. The user calculated the density of air at the inlet and outlet, applying conservation of momentum to analyze forces from pressure differences, resulting in a value of 1004. However, using conservation of mass yielded a consistent value of 1060, raising questions about the discrepancy. The nozzle's role in accelerating fluid flow is highlighted, noting that while mass flow remains constant, velocity increases and density decreases. The conversation emphasizes the complexities of applying these conservation principles in fluid dynamics.
theBEAST
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Homework Statement


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The Attempt at a Solution


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So first I found the density of the air coming in and going out. Next I used conservation of momentum with two forces caused by the pressures at the entrance and the exit of the nozzle.

I end up getting 1004 which is not the same as 1060. If I just use conservation of mass so ρVAout=ρVAin I get exactly 1060. So why is it that conservation of momentum does not work in this scenario?
 
Physics news on Phys.org
The nozzle is accelerating the flow of the fluid through the restriction. The mass flow into the nozzle is the same as the mass flow out, but the velocity has increased while the density decreases.
 
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