Tutorial for CIVL252 Hydraulics Lesson 3

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Tutorial for CIVL252 HydraulicsLesson 3

• By DUAN Huanfeng
• ceduan_at_ust.hk

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Example 1

• Problem
• A pipe system consists of a reservoir, a pipe and
  a valve. The distance from the water surface in
  the reservoir to the pipe centerline is H. The
  valve is initially closed. It is desired to
  establish a steady flow of V0 in the pipe. How
  long will it take for the velocity in the pipe to
  reach 0.99V0? Assume that the pipe is horizontal,
  the wall shear is given by the Darcy-Weisback
  equation and the liquid is incompressible.
  Assume V0 10m/s,H10m,L2m for an example.

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Solution

• For C.V., Momentum EQ. (General form)

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• Now, when the velocity reaches 0.99V0,
• Assume, then we can get the relationship curve of
  aVt/V0 to t as following formula and Figure.

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