基于联合射流的翼型动态失速流动控制研究

动态失速控制对于提高翼型气动特性具有重要意义。采用联合射流方法对翼型俯仰动态失速控制进行数值模拟,完成两方面的研究:一是射流关闭时射流通道对动态失速特性的影响,二是射流开启时不同射流动量系数对动态失速控制的影响和分析。结果表明:射流关闭时,射流通道的存在对翼型上仰过程中附着流阶段的气动特性产生不利影响,使得升力系数明显下降,但是对翼型下俯过程中失速分离流阶段的气动特性影响不明显;射流开启后,动态失速特性得到极大改善,迟滞环面积显著减小,升力增加,阻力减小,且阻力和力矩的峰值显著减小,原基准翼型力矩曲线的负阻尼区域消失。

Flow control on the airfoil dynamic stall using the co-flow jet

Dynamic stall control is of great significance for enhancement of the airfoil aerodynamic characteristics. In the present study, the co-flow jet (CFJ) flow control method is numerically investigated to control the dynamic stall caused by the pitching airfoil. Two aspects regarding the CFJ implementation are studied: the effect of the CFJ channel on the dynamic stall characteristics when the jet is switched off and the effect of jet momentum coefficient on the dynamic stall control effectiveness when the CFJ is activated. Results show that the jet channel will significantly affect the aerodynamic characteristics in the attached flow regime during pitching up, but not have obvious influence on the aerodynamic characteristics in the massively separating regime during the pitching down process. When the jet is activated, the dynamic stall characteristics is significantly improved. The areas of the hysteresis lines are significantly reduced, and the lift is significantly increased, and drag is reduced. The peaks of the drag and moment are significantly reduced. Moreover, the negative damping existing in the moment coefficient hysteresis line of the baseline airfoil is removed, leading to a completely positive damping during the entire pitching cycle.