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From: deichman@cod.nosc.mil (Shane D. Deichman)
Newsgroups: sci.military
Subject: Re: Shock waves
Message-ID: <1991Apr30.044837.5138@amd.com>
Date: 29 Apr 91 14:46:09 GMT
References: <1991Apr29.051156.4584@amd.com>
Sender: military@amd.com
Organization: Naval Ocean Systems Center, San Diego
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From: deichman@cod.nosc.mil (Shane D. Deichman)


>From: jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop)
>Someone commented that the angle of a shock generated by an aircraft is
>45 degrees divided by the Mach number.
>Actually, a better approximation is given by:
>     asin(1/M) where M is the Mach number.

I realized (after my original posting) that I goofed on my Trig.  Actually,
the correct answer should be arctan(1/M), since tan(angle) is equal to the
quotient of the "opposite" and the "adjacent."  The sound energy will diffuse
orthogonally at a Mach number of 1.0000 (by definition) to the aircraft's
direction of travel.

<very insightful lesson on Thermodynamics and wind tunnel design deleted>

-shane