【摘要】 激波自激波管口出射后感生的波系图案,以及由它感生的超压场,可简化为二维非定常激波的绕射、反射问题.这个气体动力学方程组是非线性的,其解会随着时间自行产生间断.即使其初始值为连续函数,其解也可能出现间断.这就引起了困难.本文采用欧拉坐标、人工粘性、有限差分法来求解.为写出管口的边条件,首先找出一维管道气体流动的分析解,由此算出管口处的速度、压力、密度随时间变化的曲线.计算结果同实验做了比较,二者是一致的.我们曾对激波自管口出射后的绕射,激波在地面上的斜反射,激波与垂直挡板迎面相撞后的正反射,激波的爬坡过程,以及管口涡环的形成和发展的波系图案等用纹影法做了观测,同时对管口外由波系所感生的超压场分布做了测量.本文对激波自管口出射后绕射与反射流场做了数值计算.更多还原

【Abstract】 When a shock wave travells into atmosphere from an open end of a shock-tube, an over-pressure field is induced and wave diagrams of shock diffraction and reflection form immediately. In general, one can always compute the outflow problem by solving the unsteady two-dimensional gasdynamic equations. Computing this problem numerically, the authors take advantage of Eulerian coordinates, fictitious viscosity and finite difference method. In order to decide the boundary conditions for computation at the end of tube, first we find out analytical solution for the unsteady one-dimensional flow in a shock-tube, and then the variations of the velocity, pressure and density of the flow at the open end of the tube with time. The present numerical results are in agreement with the experiments.更多还原