Fluid Mechanics local acceleration and convective acceleration

  1. 1. The problem statement, all variables and given/known data
    The velocity of the water in the pipe is given by v1=.5t m/s and v2=1tm/s, where t is in seconds. Determine the local acceleration at points 1 and 2. Is the average convective acceleration between these two points negative, zero, or positive?



    2. Relevant equations

    A figure of pipe (funnel like) that is larger at the input end with v1 and smaller end with out put speed of v2.



    3. The attempt at a solution

    I don't really know how to start answering this question, I don't have the text with me (still in delivery) and don't have any notes thats on this topic.

    My try: d (v1)/dt=0.5t so a=d(v1)/dt=.5 m/s^2
    d(v2)/dt=1t so a2=d(v2)/dt=1 m/s^2
     
  2. jcsd
  3. Shooting Star

    Shooting Star 1,979
    Homework Helper

    The local accn changes because the flow is not steady and time dependent, and the values are as you have derived.

    The convective accn is positive because a particle of fluid has to speed up due to the area at point 2 being smaller than area at point 1.

    For a steady flow, there would be convective accn only.
     
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