导弹水下点火的流体动力研究

对轴对称导弹水下点火这一非线性瞬态流动提出以下数学模型及求解方法。水流场假设为理想不可压势流,用边界积分方程法求解;喷管中的燃气流动按准一维非定常无粘完全气体流动处理,用逆步有限差分格式的特征线法求解;喷入水中的燃气流采用简化的等压泡模型,用Euler-Lagrange方法模拟气泡的演化。按照时间步进方法实现了水、气流动和物体运动的数值耦合求解。数值实验结果反映出导弹水下点火时水气流动的一些重要特性。

THE FLUID DYNAMIC RESEARCH ON THE UNDER-WATER IGNITION OF MISSILE

The fluid dynamic problem of the underwater ignition of an axisymmetric missile is studied in this paper. A mathematical model is presented for solving the nonlinear transient flow. On the assumption that the water flow is incompressible and potential and the gas flow in the jet pipe is quasi-one-dimensional and inviscid, the flows are solved by using boundary integral method and characteristic line method respectively. An isobric bubble model is adopted to simplify the jet flow ejected into water through a nozzle. The evolution of bubble is simulated by means of mixed Eulerian-Lagrangian method and computational techmique. Using the time-stepping algorithm,the calculation is accomplished successfully on the gas-water flow coupled with the missile's motion. The numerical results show some important special properties of the gas-water flow of underwater ignition of missile.