摘要
基于仿生逆向重构方法对具有静音飞行特性的长耳鸮翅膀进行拟合,得到仿长耳鸮翅膀的三维叶片模型。采用大涡模拟方法对仿鸮翼型叶片流动进行数值模拟,研究了2种雷诺数(Re=16 000,70 000)下不同攻角时的鸮翼仿生叶片的流场结构,揭示了仿鸮翼型叶片的流动控制机理。研究结果表明:基于长耳鸮翅膀的仿生翼型叶片在2种雷诺数下均具有优异的升力特性,其中Re=70 000时的升力系数相对较大,最大升力系数为1.26,但流动失速攻角也相对较大;靠近叶根处叶片前缘部分的上弯结构是仿生叶片具有较高升力系数的重要因素;随着攻角的增大,受沿叶片流动方向逆压梯度的影响,叶片表面气流无法保持附面流动状态,边界层逐渐发生分离,在叶片下游处产生了明显的不规则涡结构,从而导致流动恶化,这也是仿生叶片产生涡流噪声的原因。
Following reverse reconstruction ideals, as a bionic object, long-eared owl wing with silent flight characteristics is fitted to establish a three-dimensional bionic blade model. The flow over the bionic blade is simulated numerically with large-eddy simulation （LES） method. The flow structures at different angles of attack（AoA） are investigated to reveal the flow control mechanisms of bionic blade when Reynolds number gets 16 000 and 70 000 respectively. The numerical results show that the bionic blade based on the long-eared owl wing possesses excellent lift characteristics at two different Reynolds numbers. When Reynolds number is 70 000, the maximum lift coefficient of the bionic blade is 1.26 but with a larger stall angle. The important impact factor for the lift coefficient of the bionic blade is the bending structure near the leading edge from the blade root. Because of the influence of adverse pressure gradient, the airflow cannot be kept adhering to the blade surface and the boundary layer starts to separate gradually with decreasing of the angle of attack. The irregular vortex structures generated from the downstream of bionic blade lead to a deterioration of flow status over the bionic blade, which is also the reason of the vortex noise from bionic blade.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2016年第9期111-118,共8页
Journal of Xi'an Jiaotong University
基金
陕西省科学技术研究发展计划资助项目(2014K06-24)
高等学校博士学科点专项科研基金资助项目(20120201110064)
关键词
仿生翼型
长耳鸮翅膀
气动性能
旋涡结构
数值模拟
bionic blade
long-eared owl wing
aerodynamic performance
vortex structure
numerical simulation
