Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!umich!itivax!b-tech!zeeff
From: zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff)
Newsgroups: sci.electronics
Subject: Re: hot wire anemometers
Message-ID: <_SC=7+@b-tech.uucp>
Date: 27 Dec 89 14:30:45 GMT
References: <5653@orca.wv.tek.com> <1989Dec15.172519.22348@utzoo.uucp>
Reply-To: zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff)
Organization: Branch Technology, Ann Arbor, MI
Lines: 16

>>	"hotwire anemometer" to measure windspeed across a aircraft
>
>The idea is exceedingly simple:  you run a current through a wire, enough
>to heat it up, and measure its temperature (e.g. by using a wire whose
>resistance changes in a known way with temperature).  The stronger the
>air currents over the wire, the better the cooling and the lower the
>temperature will be.  Of course, you have to compensate for variations in
>air temperature.  In principle it's a trivial device, although I'd imagine

When I did on-board microprocessor programming for Ford, we used one to
measure air flow into the engine.  It was particularily nice because it
measures the mass of the air (ie, denser air cools it more.  Denser is not
necessarily = cooler).

-- 
Jon Zeeff    	zeeff@b-tech.ann-arbor.mi.us  or b-tech!zeeff