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Wind / Fluid Dynamics.

  • #1

Homework Statement



A sheet of aluminum of thickness .01 m lies in a parking lot. A wind blows over the top of the sheet. What is the minimum velocity that will cause the sheet to begin to rise: Assume the density of air is 1.18 kg/m^3 and aluminum is 2700 kg/m^3.

Homework Equations



Bernoulli's Equation:

82cf4ee7e0214e063ea7d24787380f8a.png


or

Archimedes Principal:

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Density = M/Vol

The Attempt at a Solution



I really have no idea where to start. Since the density of AL is different than that of the fluid, I would assume it to be a buoyant force. However, air is a strange fluid to work with, and I can't figure out the volume displaced.

I just need a hint on where to begin... maybe some links to other reading. All help would be vastly appreciated.

Thanks! Sean
 
Last edited by a moderator:

Answers and Replies

  • #2
960
0
well its much like the lift on a wing where the difference in velocities leads to a pressure gradient across the sheet.
 
  • #3
25
0
First figure out the weight per area of the aluminum sheet in N/m^2, based the numbers given. That weight per area is then the difference in pressure needed to lift the plate. Assume the air below the plate is still, and figure out how fast the air on top of it needs to be to create the pressure difference.
 

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