Pressure vs speed for liquids ?

AI Thread Summary
In a horizontal pipe with varying diameters, fluid velocity increases in narrower sections due to the principle of conservation of mass, which states that the product of velocity and cross-sectional area remains constant for incompressible fluids. This results in a higher speed of fluid particles in the narrower section compared to the wider section. According to Bernoulli's equation, as fluid velocity increases, pressure decreases, indicating an inverse relationship between speed and pressure in liquids. The pressure difference is what drives the fluid to flow faster in the narrowed area. Understanding these principles clarifies the dynamics of fluid flow in varying pipe sizes.
furkang
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pressure vs speed for liquids ? :(

Think of a pipe positioned horizontally.

Some fluid is flowing from left to right.(e.g. water)

Right side of the pipe is well narrower than left side.

Is the speed of a fluid particle at the right greater than the speed of a particle at the left?
What about their pressures?

(Perfect world no energy loss)
OR


perhaps I can NOT make such a comparison without considering any value constant.

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I am really confused please help , basically I am looking for an example which prooves inverse proportion of speed and pressure of LIQUIDS. Can you give me an example like mine? Thank you for your help...
 
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Let's assume an incompressible fluid - the density does not change - and apply conservation of mass.

\rho_1 * V_1 * A_1 = \rho_2 * V_2 * A_2

for incompressible flow \rho_1 = \rho_2 = \rho

which then leaves V_1 * A_1 = V_2 * A_2

So what does the say about the relationship between fluid velocity (speed) and area?
 
ok that's well ...

that means fluid flows faster in the narrow section. That is completely different from my thought.
 
Is it the same if we use Bernoulli's equation to see that?

I could't see where is the pressure difference
 
Considering the fluid is incompressible, helps by making density constant. Is it the pressure difference, that causes the fluid to flow faster at the place where the pipe narrows?
 
You should take it the other way round(you should obviously apply Bernoulli's equation), that static head drop occurs due to increase in velocity head.
 
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