基于改进多目标遗传算法的舰尾紊流模拟方法

Carrier airwake simulation methods based on improved multi-objective genetic algorithm

为提高舰尾紊流自由大气紊流分量仿真的可信度,提出了一种紊流数值模拟的新方法.首先,使用带有修正系数的Euler前向差分格式表示各个方向的紊流序列,同时结合智能算法的思想,把紊流相关性检验中的均方差误差和相关函数误差作为待优化目标函数,将修正系数的选择看成一个多目标优化问题,并采用改进的多目标遗传算法进行求解.最后,通过仿真算例验证了本文方法的正确性与合理性,计算结果表明该方法可以根据不同的采样步长灵活地生成所需紊流.尤其在小步长情况下,亦可得到很好符合理论值的紊流序列,可以满足虚拟飞行实验的要求.

A new numerical turbulence simulation method to enhance the credibility of simulation of carri- er airwake free-air turbulence components has been presented. At first, the turbulence sequence of each direc- tion was presented as the Euler forward different format with correction factors. Meanwhile, associated with the thought of intelligence algorithm, the mean squared error and correlation function error in turbulence correla- tion test were regarded as the optimized objective functions. And the selection of correction factors was treated as a multi-objective optimization problem. The correction factors were determined by improving multi-objective genetic algorithm. At last, the validity and rationality of this method were verified by simulation cases. The calculation results show that the required turbulence sequences can be generated flexibly with different sam- pling steps. Especially in case of some small sampling step, the simulated turbulence sequences fit the theoret- ical values very well, and the method can meet the requirement of virtual flight test.