Numerical simulation of flow characteristics behind the aerodynamic performances on an airfoil with leading edge protuberances

Engineering Applications of Computational Fluid Mechanics

卷:11

Mingming Zhang¹  Ming Zhao¹  Jianzhong Xu¹ 

[1] Institute of Engineering Thermophysics, Chinese Academy of Sciences;

关键词: IDDES method;    flow control;    bi-periodic phenomenon;    computational fluid dynamics;    vortex dynamics;   

DOI  :  10.1080/19942060.2016.1277165

来源: DOAJ

【 摘 要 】

This article presents a numerical investigation of the effects of leading-edge protuberances on airfoil stall and post-stall performance. An improved delayed detached eddy simulation (IDDES) method was adopted. As a result, to clarify the effects of ‘bi-periodic’ phenomenon around stall region, it was found that the flow separation at troughs was the main inducement of aerodynamic lift degradation within pre-stall regime and the flow pattern where vortices diverged was predominant. It was also found that the variations in flow patterns led to the gentle stall process. Furthermore, to study the statistical characteristics of unsteady vortex shedding, corresponding spectrum characteristics were also analyzed from another perspective, suggesting that the vortex shedding frequency was higher where vortices converged. Eventually, the improved performances of tubercled airfoil within post-stall regime could be attributed to the strong streamwise vortices generated by the leading-edge protuberances. Deploying the methods of vortex dynamics, the generation and evolution of the streamwise vortices were depicted. It turned out that the primary and secondary vortices were induced by spanwise pressure gradient at airfoil surface; meanwhile, vortex stretching played a key role in primary vortex evolution, which initially enhanced the strength of vortices corresponding to the acceleration of streamwise velocity.

【 授权许可】

Unknown