# I Flow Resistance of Connected Tubes

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1. Jun 24, 2016

### emh01

i want to ask how flow resistance of connected tubes with different diameters is calculated.
as you see in the uploaded image we imagine that there are 3 tubes.
tube A is 2 meters long and cross section area is 2S.
tube B is also 2 meters long but first 1 meter has 2S surface area and last 1 meter has S surface area
tube C is 2 meters and has S surface area

now: how we calculate the flow resistance of tube B? do we calculate the first and last 1 meters each and add the results or different method? how we compare the resistances of 3 tubes

if connect a water pump to left of them and want to pass the same flow rate how much pressure we have to apply. what will be the compare of pressure magnitudes (3 tubes are already fully filled with liquid before pump)

add: we accept that there is no turbulance

thanks

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Last edited: Jun 24, 2016
2. Jun 24, 2016

### Staff: Mentor

If there is no viscosity, how does the lengths of the various sections affect the pressure difference? Have you tried Betnoulli?

3. Jun 24, 2016

### emh01

You are right, it has to be "There is no turbulance"

4. Jun 25, 2016

### emh01

You are right, it has to be "There is no turbulance" can you answer according to this

5. Jun 28, 2016