The reflection of a blast wave by a very intense explosion.

Andrew W Cook,Joseph D Bauer,Gregory D Spriggs

doi:10.1098/rspa.2021.0154

Andrew W Cook, Joseph D Bauer + Show 1 more

Open Access

https://doi.org/10.1098/rspa.2021.0154

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Abstract

We demonstrate that the geometric similarity of Taylor’s blast wave persists beyond reflection from an ideal surface. Upon impacting the surface, the spherical symmetry of the blast wave is lost but its cylindrical symmetry endures. As the flow acquires dependence on a second spatial dimension, an analytic solution of the Euler equations becomes elusive. However, the preservation of axisymmetry, geometric similarity and planar symmetry in the presence of a mirror-like surface causes all flow solutions to collapse when scaled by the height of burst (HOB) and the shock arrival time at the surface. The scaled blast volume for any yield, HOB and ambient air density follows a single universal trajectory for all scaled time, both before and after reflection.

Highlights

The preservation of axisymmetry, geometric similarity and planar symmetry in the presence of a mirror-like surface causes all flow solutions to collapse when scaled by the height of burst (HOB) and the shock arrival time at the surface
The Taylor [1,2], von Neumann & Richtmyer [3] and Sedov [4] solutions for a self-similar blast wave in the strong-shock limit have been used for eight decades to estimate the yields of nuclear tests and to explain the behaviour of supernovae [5], stellar wind bubbles [6] and other high-energy phenomena that produce strong shock waves [7,8]
A universal reflection function exists for ideal blasts rebounding from perfect surfaces

Summary

Introduction

The Taylor [1,2], von Neumann & Richtmyer [3] and Sedov [4] solutions for a self-similar blast wave in the strong-shock limit have been used for eight decades to estimate the yields of nuclear tests and to explain the behaviour of supernovae [5], stellar wind bubbles [6] and other high-energy phenomena that produce strong shock waves [7,8]. During the atmospheric-testing era, weapon scientists employed Taylor’s equation to estimate the yields of 210 atmospheric tests by analysing high-speed camera films [9,10]. In most of these tests, the devices were detonated sufficiently high above the ground to ignore the shock interaction with the surface. In at least 14 of these events, the blast wave reached the ground too soon for Taylor’s equation to correctly apply to the data.

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