How to calculate the velocity reduction in pipes

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Discussion Overview

The discussion revolves around calculating the velocity of water in a system of pipes with varying diameters and lengths, starting from a larger pipe. Participants explore how to determine the velocities in the smaller pipes given certain parameters, including pressure and geometry.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant asks how to calculate the velocity of water in two smaller pipes that branch from a larger pipe, given the diameter, length, and initial velocity of the larger pipe.
  • Another participant suggests that knowing the pressure at each entry and exit point of the pipe system is essential for determining flow, noting that flow depends on the geometry of the pipes.
  • A participant acknowledges having a uniform pressure value for the pipes but expresses concern about the inability to measure pressure at each entry and exit point.
  • One participant argues that if the pressure is the same throughout the system, flow cannot occur unless there is zero friction, indicating that additional information about the system is necessary to calculate flow.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how to calculate the velocities in the smaller pipes, with differing views on the necessity of pressure measurements and the implications of uniform pressure on flow.

Contextual Notes

Limitations include the assumption of uniform pressure across the system and the lack of information regarding friction and other factors that may affect flow calculations.

Vinodhkumar
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I have a big pipe with known diameter, length and velcity at big pipe. There are two pipes dividing form the big pipe with varing diameter and length.
1) How to calculate velocity of water in these two pipes?
2) If I add one more pipe of known length and diameter, what would be the velocity in each of these pipes.

Many Thanks...
 
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You need the pressure at every entry/exit point of your pipe system. Each pipe has a specific relation "flow for specific pressure difference" (where the dependency on the absolute pressure should be small), this depends on the geometry.
 
Yes, I have pressure value for the pipes. But, it is same for all over the pipe. I won't be able to measure at each entry and exit of the pipes :(
 
If the pressure is the same everywhere, you cannot get any flow, unless the system has zero friction (in this case, the flow cannot be calculated without knowledge about the remaining system).
 

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