From: lyn@matt.ksu.ksu.edu (Myself)
Newsgroups: rec.pyrotechnics
Subject: Re: Overpressure wavefront analysis
Date: 17 Nov 1992 20:58:48 -0600
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu

billn@hpcvaac.cv.hp.com (bill nelson) writes:

>lyn@endeavor.ksu.ksu.edu (Myself) writes:
>: 
>:   Is there anyone out there who can assist me in finding information on
>: determining the shape of an advancing overpressure wave front caused by
>: detonation/rapid deflagration of a chemical/nuclear 'explosive'?
>:   I am looking, specifically, at waves-form patterns and interference on
>: the surface of the wavefront due to incidence of non-gradient air pressures
>: as they are encountered. This would seem to involved a fair amount of relatively
>: complicated fluid mechanics, as well as a base of chemical/nuclear reaction
>: predictions.

>For a large explosion, I suspect that the normal non-gradient air pressures
>would be swamped into insignificance by the explosive overpressures.

>Could you give a little more detail on what you desire?

>Bill

  Ok. Let me give it a try......

    [for this article, I will assume a chemical detonation reaction]
    If the detonation were done in an 'ideal' environment (ie absolutly
    identical gradient in every direction), the resulting wavefront would be
    (in general, forgot to state a spherical explosive with 'perfect' core -->
    surface combustion) a sphere. In reality, this is untrue due to air currents
    and pressure differences before the wavefront arrives. My project is to try
    to simulate the 'ripples' on the surface of the wavefront caused by running
    into these abnormalities. Yes, in reality the pressure difference in VERY
    small compared to the pressures involved in the wavefront itself, but they
    would still have an effect on the form - I wish to attempt to predict what
    they would look like given certain types of pressure structures..... I am
    not yet sure just what I would use for these.
       Due to the great difficulty in measuring the effects of pressure variance
    on the wavefront in reality, because of the great pressure differentials
    involved ('swamping' the signal in a LOT of noise), I need to use a computer
    I do not happen to have a CRAY sitting on my desk, and wondered just how
    complicated the math gets given certain (fairly simple - I know it gets
    hairy FAST) conditions. I do not have the necessary background in fluid
    mechanics, and I am looking for someone who can at least set me on the right
    track. Real life applications would depend on what the data showed, and I do
    not know what it will look like (if I did, why do the experiment?)

          Anyway, I hope that this helps some, and again, thanks in advance,

            	Myself (lyn@matt.ksu.ksu.edu)
		One intrigued person hoping to learn something


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