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Is it possible to convert wind MPH to lbs/square ft?
2

Is it possible to convert wind MPH to lbs/square ft?

Is it possible to convert wind MPH to lbs/square ft?

(OP)
If possible, what is the formula to convert MPH of wind to pounds per square foot?

RE: Is it possible to convert wind MPH to lbs/square ft?

Application of Bernoulli Equation should take care of that; equating velocity head to pressure head.  As posted so often, check out Flow of Fluids by Crane, for example.
Good luck.

RE: Is it possible to convert wind MPH to lbs/square ft?

I find a better basic design equation taken from the 1995 Souther Building Code

q=0.00256*V*V(MRH/33)**(2/7)

V= Wind Velocity
MRH=Mean Roof Height

and

GCp see tables 1606.2B-C and Figures 1606.2D-G

If you find this helpfull plz vote so
Cheers

RE: Is it possible to convert wind MPH to lbs/square ft?

You get Lbs/sq Ft (pressure) as a result the speed of the air in a direction parallel to the surface.  However, you also get pressure from air moving perpendicular to the surface.  Bernoulli tells you how to calculate the former.  I don't know how to calculate the latter.

Break the wind into the two components (parallel and perpendicular) and apply the two equations.

RE: Is it possible to convert wind MPH to lbs/square ft?

For flat surfaces with the wind perendicular to the surface (worst case)..

F (lbs/ft^2) = 0.0046V^2 where V is the velocity of the
wind in mph.

For semi circular surfaces then:

F (lbs/ft^2) = 0.0026V^2 where V is the velocity of the wind in mph.

And V^2 is "wind velocity squared...

Hope this helps.

firetube

RE: Is it possible to convert wind MPH to lbs/square ft?

It's been a long time since my days back in school when we covered this. . .   All I remember is that the shape of the surface has a substantial impact on the force.  That's why when you stick your hand out the window of the car going down the road, spreading your fingers can have a significant effect on the force you feel.  There's a constant that needs to be included in the equation which relates to the object shape, that constant often needs to be empirically derived.  Some standard shapes have published constants -- Firetube alludes to the constant for semicircles in his second equation above, but does not indicate what shape the first equation is for (I'd suspect a circle or a square).

RE: Is it possible to convert wind MPH to lbs/square ft?

In cars (and aircraft?) there is some concern over wind resistance. Reletive motion between the object (vehicle) and the fluid (air) results in a force on the object and turbulence, etc. in the fluid.

The force is a function of the fluid properties, reletive velocity, shape and size of the object.
Right?

A lot depends on what you mean by "pressure".
What was the original purpose of the question?

Jay

Jay Maechtlen

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