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Ball in pipe turbulant problem

  1. Oct 30, 2011 #1

    I have a vertical pipe with floating ping pong ball in it.

    I have fan at the bottom that that push the ball up.

    The pipe parameters:

    Ball parameters:

    I tried to change fan speed to move the ball but becouse turbulance the ball is not steady, and so I can not control ball hight with fan speed.

    I installed step motor at the top to open and close the hatch, it seems to be working.

    I have now problem to calculate all of it.

    If I look at the ball that floats in the air (inside the pipe) , the forces that I believe are effecting the ball are:
    fg-weight force (down)
    fd-drag force (up)
    fb-buoyant force (up)

    And I believe that there is a some turbulance force that pulls the ball down.

    I cant use stocks equations becouse Re number is more than 2300 and I cant use bernoulli equations also becouse I have turbulance.

    Eventually I need somehow to calculate the pressures ratio between two sides of the ball,

    and develop formula for ball's hight.

    Please help with this.
  2. jcsd
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