航空学报 > 2017, Vol. 38 Issue (12): 121369-121369   doi: 10.7527/S1000-6893.2017.121369

基于分段插值的水上无人机离水特性求解方法

李陟, 马东立, 杨穆清, 郭阳, 胡浩德   

  1. 北京航空航天大学 航空科学与工程学院, 北京 100083
  • 收稿日期:2017-04-28 修回日期:2017-06-19 出版日期:2017-12-15 发布日期:2017-06-19
  • 通讯作者: 李陟 E-mail:lzevan@163.com

Piecewise interpolation method for calculating sea-UAV's takeoff performance

LI Zhi, MA Dongli, YANG Muqing, GUO Yang, HU Haode   

  1. School of Aeronautic Science and Engineering, Beihang University, Beijing 100083, China
  • Received:2017-04-28 Revised:2017-06-19 Online:2017-12-15 Published:2017-06-19

摘要: 水上无人机成为无人机研究的新热点,其船体构型对离水特性影响巨大,构型参数设计合理可以减小滑跑距离和需用功率,反之会造成离水困难,甚至可能出现增加发动机功率水上飞机也无法离水的情况。这是由于其特殊的起降环境使得水上无人机起飞过程受力情况较常规飞行器更加复杂,常规飞行器起飞性能计算方法对于水上无人机不再适用,所以对水上飞机起飞离水特性的求解十分重要。CFD的发展使得利用数值计算方法代替常规的试验手段成为了可能,但直接利用CFD软件仿真求解水上无人机/飞机的离水过程难度大,耗时长,可行性低。可根据CFD计算中库朗数条件对气动力和水动力求解要求的不同,采用解耦方法分别求解不同条件下水上无人机完整构型的气动力和船体构型的水动力;同时水上无人机在起飞滑跑过程中,垂向受力小、加速度小,可将垂向受力看做近平衡状态,这成为分段插值求解方法的基础。将离水起飞过程离散化,利用分段插值方法求解得到其起飞离水特性,计算结果可以很好体现水上无人机水面滑跑的特性,与试验结果吻合良好。

关键词: 水上无人机, 离水特性, 分段插值方法, 近平衡假设, 解耦计算

Abstract: The sea-UAV has become a hot spot of UAV research recently. Sea-UAV's hull is a key factor for the takeoff procedure. The well-designed hull can reduce engine power and takeoff distance; otherwise, the UAV would hardly take off, and engine power would even increase. Because the sea-UAV has a more complex force condition due to the particular takeoff environment, the takeoff performance analysis method applied to conventional aircraft is no longer available for the sea-UAV. Therefore, it is important to analyze the takeoff performance of the sea-UAV. The development of CFD makes it possible to use numerical calculation method to replace the experimental method, but it is not realizable to predict the multiphase performance of the sea-UAV by using CFD directly for it is time consuming and has enormous amount of calculation. In this paper, a decoupled calculation method is developed to predict the aerodynamic and hydrodynamic forces separated based on the different demands of Courant number. Meanwhile, the force in the vertical direction is assumed to be near balanced due to quite small resultant force and acceleration in this direction during takeoff. Based on this assumption, the discrete takeoff procedure is calculated by the piecewise interpolation method. The results can explain sea-UAV's takeoff characteristics, and match the experimental data well.

Key words: sea-UAV, takeoff performance, piecewise interpolation method, near balance assumption, decoupled calculation

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