The Riemann problem and interaction of waves in gas dynamics

The initial-value problem constructed by Riemann (1860) to describe the motion of an ideal gas in a shock tube is investigated analytically, with an emphasis on the mathematical aspects. Topics addressed include the simplest Riemann model and the interactions of elementary waves (shock waves, centered rarefaction waves, and contact discontinuities), one-dimensional isothermal flow, one-dimensional adiabatic flow, and two-dimensional flow. Particular attention is given to the Riemann problem for a scalar conservation law, the interaction of a shock wave overtaking another in steady two-dimensional flow, and the diffraction of a planar shock along a compressive corner. 92 refs.