Timeline for Can the continuity equation and Bernoulli contradict each other?
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| May 28, 2018 at 11:23 | history | edited | Sputnik | CC BY-SA 4.0 |
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| May 28, 2018 at 11:22 | answer | added | Sputnik | timeline score: 1 | |
| May 28, 2018 at 10:52 | comment | added | Sputnik | Yes - have worked with gauge pressure throughout the question. | |
| May 24, 2018 at 14:27 | comment | added | nluigi | Have you considered that the pressure at the inlet of the larger pipe is given as a gauge pressure? | |
| May 24, 2018 at 14:13 | history | edited | Qmechanic♦ |
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| May 24, 2018 at 14:00 | comment | added | Sputnik | I'm still not 100% sure that I have the correct idea, but barring any other forthcoming answers later today I might try fleshing out this answer fully below for others to correct or comment on... | |
| May 24, 2018 at 13:58 | comment | added | Sputnik | Thanks for the comment. In light of this question I've noted that a speed of $62.5$ m/s at the exit leads to a pressure of $-1734$ kPa. I wasn't aware of using the idea of cavitation forming at a pressure of roughly $-1$ atm, so taking that into account, the velocity peaks at about $25.3$ m/s at the exit. With cavitation occurring, the upper pipe cannot possibly be full, leading to a reduced cross-sectional area and therefore ensuring that continuity is maintained. | |
| May 24, 2018 at 13:37 | history | tweeted | twitter.com/StackPhysics/status/999645563481141248 | ||
| May 24, 2018 at 13:25 | comment | added | nluigi | FYI: Continuity is like the laws of thermodynamics but for fluid dynamics, if your model doesn't follow it then your model is most probably incorrect. | |
| May 24, 2018 at 13:23 | comment | added | nluigi | It seems to me that you would use continuity to calculate the velocity in the smaller pipe and then Bernoulli to calculate the corresponding pressure. From the problem description there is no indication that the smaller pipe is necessarily at atmospheric pressure. | |
| May 24, 2018 at 12:50 | review | First posts | |||
| May 24, 2018 at 13:27 | |||||
| May 24, 2018 at 12:47 | history | asked | Sputnik | CC BY-SA 4.0 |