Bernouilli's principle pipe flow problem

[pianopanda]

Homework Statement

On a horizontal pipe with flowing water on point 1 there is a vertical pipe with water up to some point. On another point 2, we have a pitot tube (L shaped) against the water flow and the lever on the vertical part is higher that on point 1. If the water flow stops what happens to the levels on the vertical tubes ?

Homework Equations

Bernouilli's equation : 1/2 ρv²+ ρgh+ P= constant

The Attempt at a Solution

On point 1 we only have the hydrostatic pressure. On point 2, the dynamic pressure is added to the hydrostatic pressure because of the shape of the tube so the water column will be higher. According to the principle that the total pressure should be conserved, then the dynamic pressure should completely change into hydrostatic pressure and the level on 1 should rise to the level on 2. This however seems quite counter intuitive to me so I would really appreciate your points of view! Thanks in advance

 

[voko]

Are you concerned with the situation when the flow is stopped abruptly, or when slowly?

 

[pianopanda]

from what i understood it was stopped abruptly

 

[voko]

You may want to read up on water hammer. You can experiment in your garden or kitchen, too.

 

[pianopanda]

I don't think it's the case of a water hammer. It's just a theoretical situation where we imagine the flow stopping "abruptly" but without the pressure wave.

 

[voko]

If it is abruptly, then there is a pressure wave - all that energy cannot just disappear. If there is no pressure wave, then it cannot be abruptly. You have to make a choice, you cannot have it both ways.