Numerical Analysis of Unsteady Compressible Gas Dynamics of Varied Area Channels:Applied to Gas Dynamic Laser Start.

摘要

A method of characteristics technique for one-dimensional unsteady flow with an indefinite number of discontinuities in a varied area channel has been developed. The technique is an improvement of the Hartree technique. The technique has the desirable features of both the grid of characteristics method and the inverse specified solution point method. In the present method the solution points are determined by the intersection of right-running wave characteristics and specified constant time lines. The algorithm permits the formation of an indefinite number of right-running shocks and left-running shocks in the flow field. The shocks can dissipate,combine or depart from the channel. Shocks of opposite families can cross each other. Left running shocks can move upstream,downstream or remain stationary. A contact surface can be analyzed. A fluid particle can be followed in the flow. A numerical algorithm for computing internal flows of the type encountered in the start of gas dynamic lasers has been developed and programmed. Accuracy studies were conducted. (Modified author abstract)