[pyar] Calcular Sensacion Termica con Python

[Sebastian Bassi]

2011/4/20 Juan Carlos Ojeda <juancarlospaco en gmail.com>

> No necesito que sea preciso, una solucion out of the box seria ideal, como
> seria la cosa entons ?
>
>
>>> v=20
>>> t=20
>>> 33+(t-33)*(.474+.454*((v-.0454)*v)**.5)
-91.067948482542661

Me da cualquier cosa pero supongo que porque no se cuales son las unidades
que hay que usar para esa formula en particular.

Estab mirando wikipedia y dice esto (en ingles y fijate que segun que
formula sea las unidades que usan):

The original formula for the index was:
[image: WCI=(10\sqrt{V}-V+10.5) \cdot
(33-T_{a})][4]<http://en.wikipedia.org/wiki/Wind_chill#cite_note-3>
[5] <http://en.wikipedia.org/wiki/Wind_chill#cite_note-4>Where:*W**C**I* =
Wind chill index, kcal/m2/h*V* = Wind velocity, m/s*T**a* = Air temperature,
°C

The general public seems to have been put off by the strange sounding units,
either the old ones or the newer watts per square metre, and developed a
strong preference for Equivalent Temperature, a deceptive simplification
that only seems to be easier to understand. Even in the cold areas of
Canada, broadcast media began to switch to the newer method of reporting
after metrification.
[edit<http://en.wikipedia.org/w/index.php?title=Wind_chill&action=edit&section=4>
]North American wind chill index

In November 2001 the National Weather
Service<http://en.wikipedia.org/wiki/National_Weather_Service>
implemented
the new wind chill index, used by the U.S. and Canadian weather services,
which is determined by iterating a model of skin temperature under various
wind speeds and temperatures. The model used standard engineering
correlations of wind speed and heat transfer rate. Heat transfer was
calculated for a bare face in wind, facing the wind, while walking into it
at 1.4 metres per second (3.1 mph). The model corrects the officially
measured wind speed to the wind speed at face height, assuming the person is
in an open field.[6] <http://en.wikipedia.org/wiki/Wind_chill#cite_note-5> The
results of this model may be approximated, to within one degree, from the
following formula:
[image: T_{wc}=13.12 + 0.6215 T_a-11.37 V^{+0.16} + 0.3965 T_a
V^{+0.16}\,\!]where [image: T_{wc}\,\!] is the wind chill index based on the
Celsius scale, [image: T_a\,\!] is the air temperature in °C, and [image:
V\,\!] is the air speed in
km/h<http://en.wikipedia.org/wiki/Kilometres_per_hour> measured
at 10 metres (33 ft), standard
anemometer<http://en.wikipedia.org/wiki/Anemometer>
 height).[7] <http://en.wikipedia.org/wiki/Wind_chill#cite_note-6>

The equivalent formula in US customary
units<http://en.wikipedia.org/wiki/US_customary_units>
 is:
[image: T_{wc}=35.74+0.6215 T_a-35.75 V^{+0.16}+0.4275 T_a V^{+0.16}\,\!]
where [image: T_{wc}\,\!] and [image: T_a\,\!] are measured in °F, and [image:
V\,\!] in mph <http://en.wikipedia.org/wiki/Miles_per_hour>.
------------ próxima parte ------------
Se ha borrado un adjunto en formato HTML...
URL: <http://listas.python.org.ar/pipermail/pyar/attachments/20110420/ece6089d/attachment.html>