On the characteristics of a spark generated shock wave

Recent experiments involving shock waves propagating through weakly ionized plasmas have raised questions regarding interpretation of the experimental results. In aid of analyzing these experimental results, shock waves initiated by a simulated spark and their subsequent propagation in a cylindrical tube containing argon initially at 30 Torr and 300 K, have been analyzed numerically in this paper. Numerical solutions to the compressible Navier-Stokes equations are considered under the four conditions of induced flow (a) without wall friction, (b) with wall friction, (c) with wall friction and purely axial thermal gradients, and (d) with wall friction and both axial and radial thermal gradients. Although plasma processes have not been simulated, it is found that the effects of wall shear and thermal gradients alone are sufficient to explain most of the experimental observations. This work represents a first step in the analysis of this problem before plasma effects can be modeled. (C) 2000 American Institute of Physics. [S1070-6631(00)01804-3].