整体运动网格法在飞机水上迫降模拟中的应用

Application of Global Moving Mesh in Aircraft Ditching Simulation

对NACA TN 2929模型的水上迫降性能进行数值模拟研究。采用有限体积法求解RANS方程和r-k-ε湍流模型,采用VOF方法捕捉水气交界面,采用六自由度模型和整体动网格技术处理飞机和水面之间的相对运动。在计算过程中,整个计算域内的网格都随飞机做刚体运动,从而有效避免了传统变形网格技术中的计算成本高、网格质量低的问题。利用该数值方法首先模拟了二维圆柱自由落体入水冲击,计算结果和实验数据吻合较好;然后详细研究了NACA TN2929模型各部件在水上迫降过程中的作用,计算结果表明在分析飞机水上迫降性能时,气动载荷的影响不可忽略。

This paper numericaly investigated the ditching characteristics of the NACA TN 2929 model. In the simulation method, the RANS equation andr-k-ε turbulence model were solved by ifnite volume method; the VOF method was used to capture the water-air interface; the six degree of freedom model and the Global Moving Mesh （GMM） method were used to deal with the relative motion between the water and the object. In the calculation process, mesh in the whole computational domain and boundaries move together with the aircraft, to avoid the high computational expense and low quality mesh in the traditional mesh deformation method. This numerical method was applied to simulate the water impact of a 2D cylinder in free fal, and the results show a good agreement with the experimental data. The effect of each aerodynamic part of the NACA TN 2929 model on the ditching behavior was studied in detail, and the results show that aerodynamic loads cannot be ignored when analyzing the ditching motion of the aircraft.