基于预估校正和嵌套网格的虚拟飞行数值模拟

 针对导弹虚拟飞行数值模拟问题,发展了空气动力学/飞行力学数值计算方法和软件。控制方程为非定常雷诺时均Navier-Stoker(RANS)方程和刚体六自由度运动方程;流场求解器为有限体积法结构网格求解器,时间推进采用双时间步法,湍流模型为Spalart-Allmaras一方程模型;采用Adams预估校正法实现飞行力学方程与流场控制方程的耦合计算;使用嵌套网格方法模拟多体运动。首先模拟了美国国家航空航天局(NASA)窄条翼导弹模型纵向虚拟飞行,研究耦合方式和时间步长的影响。仿真结果表明,双时间步三阶Adams耦合方法,同等精度下可以显著增大时间步长,缩短仿真时间。最后,采用该方法模拟了导弹自由摇滚特性和纵向虚拟飞行,模拟结果与试验值吻合较好。

Numerical Simulation of Virtual Flight Based on Predictioncorrection Coupling Method and Chimera Grid

An aerodynamic and flight dynamic coupling computation method and software are developed to simulate the virtual flight of a missile.The control equations are unsteady Navier-Stokes equations and rigid body 6-dof flight dynamic equations.The flow solver is a finite-volume solver of structure grid which solves unsteady Reynolds averaged Navier-Stokes(RANS) equations with dual time stepping and a Spalart-Allmaras turbulence model.Adams prediction-correction method is used to couple the aerodynamic and flight mechanic computation,and the chimera method is used to simulate relative motions.This methodology is used to simulate the longitudinal virtual flight for a NASA missile with long middle strakes to study the effects of coupling method and time step.Simulation results show that the third order Adams prediction-correction method can simulate in a much higher time step while keeping an equal precision level to obviously decrease simulation time.Finally, this approach is used to simulate free-to-roll motions and longitudinal virtual flights with results showing good agreements with wind tunnel test.