Why is b higher than a and c? If Q=AV and A increases shouldn't v decrease. And in that case kinetic energy decrease? And How is a and c equal? Since energy is needed to ovrecome the potential energy shouldn't kinetic energy decrease?
Assume:
Volumetric Flow rate, and thus mass flow rate, is conserved.
Then the problem boils down to Conservation of Energy. Slower fluid velocity translates into higher pressures according to Bernoulli's equation. Higher internal pressure means the pitot tube will show a higher fluid height to indicate as such.
Since section "b" has a larger cross sectional area, we know that the fluid must be traveling slower (due to our assumptions). The kinetic energy of the fluid didn't disappear from section "c" to "b", so the missing kinetic energy must be stored in the form of pressure. This pressure (energy storage) is what allows the fluid to move from section "b" to section "a".
It is not really about flow rate. It is about Bernoulli's eq.
So, flow rate = Q = A1V1=A2V2. In other words, flow rate remains constant and as pipe area adjusts, so therefore does flow velocity. When you put this into the context of Bernoulli's:
you will see that as velocity INCREASES, height z must DECREASE. Therefore, B will have the highest height because it is moving at the lowest velocity. C and A will have equal heights, which are lower than B, because they have the same velocity which is higher than that of B. The pipe widths being on different levels is a trick. It doesn't matter.
This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies and terms of service.
