🚀 go-pugleaf

>the equation  h = ( a + b * sqrt(v) - c * v ) ( s - t)
>
>  where   h= heat loss (btu's/sq.f. of skin)
>          t= air temperature (farenheit)
>          v= wind speed (mi/hr)
>          s= 91.4 deg F (neutral skin temp)
>          a = 2.14, b = 1.37, and c=0.0916 (experimentally determined
>                                             constants)
>
>can be used to determine the 'wind-chill index'
>
>to do so, simply note that the wind-chill index is the equivalent
>temperature which has the same heat loss as with a temperature
>with a 4 mi/hr wind ( the speed of a brisk walk).
>
>so if we denote the wind-chill index by te (for temp. equiv.), we
>merely need to solve
>
>(a+b*sqrt(v)-c*v)*(s-t)=(a+b*sqrt(4)-4*c)*(s-te)
>
>for te.



umm... if I do this right, I get
(s-te) = (a+b*sqrt(v)-c*v)*(s-t)
         -----------------------
         (a+b*sqrt(4)-4*c)

or

te = s - (a+b*sqrt(v)-c*v)*(s-t)
         -----------------------
         (a+b*sqrt(4)-4*c)

and filling in the constants and combining terms this yields

te = 43.33 - .4741t - 1.855v + .0203tv + 27.74 sqrt(v) -
     .3035t(sqrt(v))

and trying this out in a program:

chill -10 10
The wind chill is 124.81 for a temp of -10.00 and a wind of 10.00 mph.

but it should be -34, from my table of wind chill out of
the "Information Please" almanac.

did I screw up the algebra, or was the original formula wrong?


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