- #1
bc1235
- 9
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I was surprised at the number of people thinking they should "ride out the storm" when Hurricane Mathew moved up the coast. They are assuming that because they've been in a cat 1 or 2 that a 3 or 4 is nothing to worry about. I was trying to explain to someone that force is not linier with delta velocity. I had to do some hunting to find a formula. f = A * e * v² where f = force, A = Area, e = mean density of air. v = velocity.
I used 1.225 kg/m3 for e and assume an area of 1 for simplicity. So Assuming a solid static wall at all velocities I simplified the formula to f = e * v² which, when I plot it appears to follow the curve I'd expect however I've seen other posts here now that make me question the equation I'm using.
Another post here was looking at force of wind at 100 MPH and was calculating a force of .17 psi and assumed a force of 1.7 psi at 1000 mph. That doean't make sense to me. Pressure shouldn't be directly proportional to velocity. However someone responding said that those were the correct numbers.
So now I question my equation. I know the numbers I used were metric but I found I found aproximately 2.35 for imperial at between 60º and 70º F.
So, is the equation I'm using correct? Are the numbers they are getting accurate? Am I missing something in my equation? Actually I would like to plot it in both metric and imperial units.
Thank you in advance for use of your brain power.
Bruce
I used 1.225 kg/m3 for e and assume an area of 1 for simplicity. So Assuming a solid static wall at all velocities I simplified the formula to f = e * v² which, when I plot it appears to follow the curve I'd expect however I've seen other posts here now that make me question the equation I'm using.
Another post here was looking at force of wind at 100 MPH and was calculating a force of .17 psi and assumed a force of 1.7 psi at 1000 mph. That doean't make sense to me. Pressure shouldn't be directly proportional to velocity. However someone responding said that those were the correct numbers.
So now I question my equation. I know the numbers I used were metric but I found I found aproximately 2.35 for imperial at between 60º and 70º F.
So, is the equation I'm using correct? Are the numbers they are getting accurate? Am I missing something in my equation? Actually I would like to plot it in both metric and imperial units.
Thank you in advance for use of your brain power.
Bruce