自由涡数值计算的参数影响分析

介绍了自由涡方法中多个参数的影响,包括桨叶离散段数、有弯度翼型的涡网格密度、尾迹的长度.从桨叶根部到桨尖采用分区离散,内段区域离散稀疏,桨尖区域离散细密,根部区域的离散密度对计算结果影响不大,桨尖区域的离散密度对计算结果影响较大;采用涡网格模拟有弯度的翼型,涡网格的密度对计算结果有较大影响,但密度过大对于计算精度提高影响不大.悬停和小速度前飞状态,取9圈自由涡尾迹就能够得到较好的计算结果,爬升和大速度前飞状态下,取7圈自由涡就能够得到足够的计算精度.在上述参数中,自由涡圈数对计算时间的影响最大. 

Parameter influence analysis of free-wake numerical method

The parameter influence of rotor free-wake method was presented,including blade discrete segments,vortices grid density and wake length.Several areas were made from blade root to blade tip.The inside area was segmented coarsely but the tip area was segmented more densely.The segment density of inside area has lower influence on the numerical result than that of tip area.Vortices were used to model unsymmetrical aerofoil.The density of vortices can affect the numerical result obviously.Proper density is needed and too dense vortices grid can not improve the accuracy of numerical result.For the hover and low speed flight state,9 loops of wake is enough to get accurate numerical result,and for climb and high speed flight state 7 loops of wake is enough.The influence of time cost of these parameters was also discussed and wake length has the most influence.