一维 问题，即激波管问题，是一个典型的一维可压缩无黏气体动力学问题，并有 解析解。对它采用二阶精度 两步差分格式进行数值求解。-A one-dimensional problem that the shock tube problem is a typical one-dimensional inviscid compressible gas dynamics, and analytical solutions. It uses a two-step second order accuracy