中文摘要：

以基于NACA 0018翼型的锯齿尾缘仿生叶片为研究对象,采用大涡模拟的方法研究锯齿相对齿宽与相对齿高对锯齿尾缘叶片的气动特性和非定常绕流流场的影响规律和机制.研究表明,尾缘锯齿参数对叶片气动性能的影响是复杂的非线性过程,在一定来流攻角范围内能提高升阻比,但失速提前.如在9.4°~14.8°来流攻角范围内,不同相对齿宽系列叶片的升阻比高于原始叶片,升阻比与锯齿相对齿宽之间没有线性关系.研究还表明,锯齿尾缘能延迟边界层分离,加速尾迹的流动掺混和能量扩散,改变非定常涡结构和涡脱落频率.相对齿高的变化对非定常流动特性的影响更为显著.尾缘锯齿诱导的二次湍流射流和吸力面侧反向涡对改变了原始叶片的绕翼环量,进而影响锯齿尾缘叶片的气动特性和绕流流场特性.

英文摘要：

To research the aerodynamic characteristics and unsteady flow fields of NA- CA 0018 airfoil with or without serrated trailing edge based on large eddy simulation, the in- fluences or rules were discussed by changing relative wave length and relative wave ampli- tude of trailing edge serrations. It was found that the effect of trailing edge serration parame- ters on aerodynamic performance of airfoil was a complex nonlinear process, lift-drag ratio increased at special angle of attack, the stall occured when the critical angle of attack of the bionic blade with trailing edge serrations was smaller. As an example, the lift-drag ratios of serrated trailing edge blades with different relative wave lengths were higher than original blade when angle of attack was between 9.4° and 14. 8°, but there wasn＇t a linear relationship and energy diffusion, and change the structure of unsteady vortex and vortex shedding fre- quency. Changes of wave amplitude of trailing edge serrations influenced the unsteady flow characteristics more significantly. The turbulent jet and the counter-rotating vortices on suc- tion surface occurred by the trailing edge serrations changed the circulation of the original blade, therefore aerodynamic characteristics and flow field of bionic blade with serrated trai- ling edge were influenced extremely.