Blast Wave Propagation

Abstract

In the previous sections I have addressed several methods of generation of blast waves. The propagation of the blast wave away from the source is a function of the geometry in which the blast wave is moving. A distinction needs to be made between the geometric representation of the blast wave and the number of degrees of freedom the expansion is permitted. A linear expansion, such as a shock tube, a cylindrical expansion such as generated by a long cylindrical charge and a spherical expansion and decay can all be accurately represented in one dimension. For linear propagation the cross section into which the blast wave is propagating remains constant. A cylindrical expansion may be accurately represented by increasing the cross section into which the blast is propagating proportional to the range to which it propagates. Similarly, a spherical expansion can be accurately represented by increasing the cross section proportional to the square of the range. This may be thought of as treating a unit length for the cylindrical case or a constant solid angle for the spherical expansion.