为了揭示鸟类翅膀特征结构与其气动性能的关系,从而为高效低噪仿生翼型的设计和开发提供有益的基础信息和仿生学理论支撑,使用三维激光扫描仪对4种常见鸟类(红嘴相思鸟、黑尾蜡嘴雀、八哥、家鸽)进行实体扫描,将真实鸟翼进行数字化建模,构建了4种三维仿生翼模型,并截取得到沿翼展方向不同截面位置处的仿生翼型。运用数值模拟方法对仿生翼的气动性能和噪声特性进行研究,并比较了不同攻角和不同雷诺数下4种仿生翼的气动性能。研究发现:4种仿生翼的气动性能曲线变化趋势一致,雷诺数对于4种仿生翼的影响效果也是相似的;当雷诺数大于100 000时,仿生翼气动性能的雷诺数效应并不明显;八哥仿生翼的气动性能良好,但适用的攻角范围较小;红嘴相思鸟仿生翼的升阻比相对较低,但对攻角的变化不敏感;擅长飞行的鸟类翅膀更明显地分化成两个部分,靠近翅根的部分整体弯曲,翼型不对称,靠近翅尖的部分基本平直,为对称翼型。噪声模拟结果还揭示了特定飞行状态下仿生鸟翼的气动噪声特性,可以推测,仿生翼的尾迹特征和飞行速度是影响其噪声分布情况的关键因素。
To reveal the relationship between the special structures of birds' wings and their aerodynamic performances and hence provide useful information and support based on bionics theory for the design and development of high efficiency and low noise bionic airfoils,four kinds of birds(red billed Leiothrix,black tailed Grosbeak,starling,pigeon)as research objects were scanned using 3Dlaser scanner to reconstruct bionic wing models.Three-dimensional bionic airfoils from various sections of the birds' wings were obtained.Numerical simulation was conducted to investigate the aerodynamic performances and corresponding noise characteristics of the bionic wings.Firstly,through comparing the aerodynamic performances of the wings at varied attach angles and different Reynolds numbers,it was found that the performance curves of the four bionic wings change consistently,and are influenced by the Reynolds number in the similar way.When Reynolds number increases beyond 100 000,the performances of the bionic wings show little difference with the change of Reynolds number.The starling bionic wingperforms better but only suitable for the case where the attack angle has little change.By contrast,the wing of red billed Leiothrix performs worse while its performance is not dependent on the angle of attack.Besides,the wings of good-at-flying birds can be divided into two parts:the root part of the wing is overall bending with asymmetrical airfoil;the top part is generally straight with symmetrical airfoil.The noise characteristics in certain cases were revealed according to the results of noise simulation.Also,the wake and flying speed can influence the distribution of noise.