Dettagli

Additional Info

Plotted with Gnuplot 4.2.2. Isobars are based on numerically solved formulae from the internal help pages of the BLAST software, the H_opt curve is an analytical fit using the inversely plotted formula

${\displaystyle {{\mathit {GR}}_{\mathit {OP}} \over \mathrm {m} }=\left(\left(9{,}54\cdot 10^{-3}\,{H_{\mathit {OP}} \over \mathrm {m} }^{1{,}95}\right)^{4}+\left(3{,}01\,{H_{\mathit {OP}} \over \mathrm {m} }^{0{,}75}\right)^{4}\right)^{1/4}\,.}$

This function should fit both BLAST output and Figures 3.73a-c taken from Glasstone, Dolan, The Effects of Nuclear Weapons, 1977 (EoNW77) as a compromise. Both sources differ slightly. EoNW77 shows the maximum low-pressure ranges at somewhat lower altitudes whereas for high pressures >40 psi BLAST shows no optimum altitudes at all (see the innermost isobar). However, since numerical fitting of curves taken from a paper would be a Sisyphean task while BLAST already outputs plottable numbers, only isobars from the latter are plotted here.

A note on the new version on June 6 2022: The interpolation between the Mach zone and the regular reflection zone has been altered in order to steepen the "knees". This provides a better fit to the Figures 3.73a-c in EoNW77 where the relation of GR to H is actually not unique but features local minima at the onsets of the "knees" for intermediate overpressures. In addition, contours for 1.5, 7 and 15 psi have been added.

Why psi?

Most sources, e.g. Glasstone & Dolan (1977) or Carey Sublette's Nuclear Weapon Archive use pounds per square inch as pressure units. As a rule of the thumb, e.g. most non-reinforced buildings are destroyed for overpressures above 5 psi. However, the pressures can easily be converted into SI units, e.g. kilopascals, where 1 psi = 6.8947573 kPa or, roughly, one psi equals seven kPa.

Additional notes

A note on Gnuplot SVG terminal: Set size variable as "fixed" (the default in Gnuplot), not "dynamic", to ensure correct aspect ratio. This was the reason for uploading a 2nd version.

Licenza

Io, detentore del copyright su quest'opera, la rilascio nel pubblico dominio. Questa norma si applica in tutto il mondo. In alcuni paesi questo potrebbe non essere legalmente possibile. In tal caso: Garantisco a chiunque il diritto di utilizzare quest'opera per qualsiasi scopo, senza alcuna condizione, a meno che tali condizioni siano richieste dalla legge.