微型扑翼飞行器的改进非定常涡格法

为在保证较高计算精度的前提下高效地进行扑翼飞行器(MAV)气动特性计算,提出了一种MAV非定常涡格法(UVLM)的改进算法.在算法中充分考虑翼面瞬时形变及诱导阻力等对MAV流场及气动力的影响,并在其尾涡模型中增加对尾迹涡环畸变及粘性耗散等的建模,使算法模型能更好地反映MAV的翼面气动状态.编程实现并通过实例验证了算法的有效性和快速性;为将UVLM引入MAV优化迭代,还研究了尾涡剔除对算法效率及精度的影响,结果表明在算法模型中剔除MAV尾部一定距离处的尾涡后,可在保证算法精度的前提下大幅减少运行时间,表明该算法在MAV结构优化中存在一定的潜力.

IMPROVED UVLM FOR FLAPPING-WING AERODYNAMICS COMPUTATION

To calculate the aerodynamics of flapping-wing micro air vehicle(MAV) with the high efficiency and the engineering-oriented accuracy,an improved unsteady vortex lattice method (UVLM) for MAV is proposed.The method considers the influence of instantaneous wing deforming in flapping,as well as the induced drag,additionally models the stretching and the dissipation of vortex rings,and can present the aerodynamics status on the wing surface.An implementation of the method is developed.Moreover,the results and the efficiency of the proposed method are verified by CFD methods.Considering the less time cost of UVLM,for application of UVLM in the MAV optimization,the influence of wake vortex ignoring time saving and precision is studied.Results show that saving in CPU time with wake vortex ignoring the appropriate distance is considerable while the precision is not significantly reduced.It indicates the potential value of UVLM in the optimization of MAV design.