<DOC>
<DOCNO>
262
</DOCNO>
<TITLE>
the formation of a blast wave by a very intense explosion .
</TITLE>
<AUTHOR>
taylor,g.i.
</AUTHOR>
<BIBLIO>
proc. roy. soc. a, 201, 1950, 159.
</BIBLIO>
<TEXT>
this paper was written early in 1941
and circulated to the civil defence research
committee of the ministry of home security
in june of that year .  the present writer
had been told that it might be possible
to produce a bomb in which a very large
amount of energy would be released by
nuclear fission--the name atomic bomb had
not then been used--and the work here
described represents his first attempt to form
an idea of what mechanical effects might
be expected if such an explosion could occur .
in the then common explosive bomb mechanical
effects were produced by the sudden
generation of a large amount of gas at a high
temperature in a confined space .  the
practical question which required an answer
was ..  would similar effects be produced
if energy could be released in a highly
concentrated form unaccompanied by the
generation of gas .qm  this paper has now
been declassified, and though it has been
superseded by more complete calculations,
it seems appropriate to publish it as it was
first written, without alteration, except for
the omission of a few lines, the addition of
this summary, and a comparison with some
more recent experimental work, so that
the writings of later workers in this field may be appreciated .
  an ideal problem is here discussed .  a finite
amount of energy is suddenly released
in an infinitely concentrated form .  the motion
and pressure of the surrounding air is
calculated .  it is found that a spherical shock
wave is propagated outwards whose
radius r is related to the time t since the explosion
started by the equation
where is the atmospheric density, e is
the energy released and s a calculated
function of, the ratio of the specific heats of air .
  the effect of the explosion is to force most
of the air within the shock front into a
thin shell just inside that front .  as the front
expands, the maximum pressure decreases
till, at about 10 atm., the analysis ceases
to be accurate .  at 20 atm. 45 of
the energy has been degraded into heat which is
not available for doing work and used
up in expanding against atmospheric pressure .
this leads to the prediction that an
atomic bomb would be only half as efficient, as
a blast-producer, as a high explosive
releasing the same amount of energy .
  in the ideal problem the maximum pressure is
proportional to r, and comparison
with the measured pressures near high explosives,
in the range of radii where the two
might be expected to be comparable, shows that
these conclusions are borne out by
experiment .
</TEXT>
</DOC>
