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研究了三维空间大气紊流场生成及其在大型飞机实时飞行仿真中的应用。分析了针对大型飞机飞行仿真的扰动风场的建模需求。通过在频域空间直接进行蒙特卡罗法随机抽样,经三维傅里叶逆变换获得空间大气紊流场。采用Von Karman模型,更加准确地描述大气紊流场特征。运用傅立叶变换的复共轭对称特性,保证最终生成实的紊流场。通过无因次化方法解决了变尺度和变强度的紊流场生成问题。针对生成的空间紊流场设计了紊流梯度的计算方法。针对飞机连续穿越紊流场的问题,提出基于空间对称扩展的紊流场扩展方法。经时域相关性检验证明,基于该方法生成的紊流场与传统时域方法相比,具有较好的空间互相关特性。最后针对Boeing747飞机,给出了一个在空间紊流场中的飞行仿真实例。与传统质点化模型的仿真结果相比,基于空间紊流场和四点模型的算法更能表现出飞机穿越紊流场飞行的随机特性。
The generation of atmospheric turbulence field in three-dimensional space and its application in real-time flight simulation of large aircraft are studied. The modeling requirements of disturbance wind field for large aircraft flight simulation are analyzed. The atmospheric turbulence field is obtained by the random sampling of the Monte Carlo method in the frequency domain space and the inverse Fourier transform of the three-dimensional space. The Von Karman model is used to describe the characteristics of atmospheric turbulence more accurately. The complex conjugate symmetry property of Fourier transform is used to ensure the final generation of real turbulent flow field. Through the dimensionless method, the problem of turbulence field generation with variable scale and strength is solved. A method of calculating the turbulent gradient is designed for the generated turbulence field. Aiming at the problem that the aircraft continuously crosses the turbulent flow field, a turbulent flow field expansion method based on the symmetrical space expansion is proposed. The time-domain correlation test proves that the turbulent flow field generated based on this method has better spatial cross-correlation characteristics than the traditional time-domain method. Finally, for Boeing747 aircraft, an example of flight simulation in space turbulence field is given. Compared with the simulation results of the traditional particle model, the algorithm based on the space turbulence field and the four-point model can better show the random characteristics of the aircraft flying through the turbulent flow field.