Abstract—

Two-dimensional flow of the pulsed co-flow jet (CFJ) and the influence of the pulsed parameters on the lift and power consumption are investigated numerically. Firstly, the jet channel of traditional CFJ airfoil is improved. The stall margin is increased by 3° compared with the corresponding traditional CFJ airfoil, and the lift is increased, while the drag is reduced significantly. Then, the influence of the pulsed parameters, such as the pulse waveform, including sinusoidal and rectangular waves, the duty cycle, and the pulse frequency on the lift and power consumption are presented and analyzed in detail. It is concluded that, compared with the steady CFJ, the pulsed CFJ possesses much better ability in suppressing separation and can improve the lift characteristics significantly with limited cost of power consumption. For example, at an angle of attack of 20° flow separation occurs severely, when the steady CFJ is adopted; however, the airflow becomes fully attached on the upper airfoil, when the rectangular pulsed CFJ is employed. As a result, the lift corresponding to the rectangular wave is higher than that of the sinusoidal wave. The results also indicate that the lower duty cycle and pulse frequency can lead to the higher lift but with more power consumption.

中文翻译：

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脉冲共流射流的二维数值研究

摘要——

数值研究了脉冲共流射流（CFJ）的二维流动和脉冲参数对升力和功率消耗的影响。首先，改进了传统CFJ翼型的喷射通道。失速裕度比对应的传统CFJ翼型增加3°，升力增加，阻力显着降低。然后，详细介绍和分析了脉冲参数，例如脉冲波形，包括正弦波和矩形波，占空比和脉冲频率对升力和功耗的影响。得出的结论是，与稳态CFJ相比，脉冲CFJ具有更好的分离抑制能力，可以在有限的功耗成本下显着改善升力特性。例如，当采用稳态CFJ时，在20°攻角处发生严重的流动分离；然而，当采用矩形脉冲 CFJ 时，气流完全附着在上翼型上。结果，矩形波对应的升力高于正弦波的升力。结果还表明，较低的占空比和脉冲频率可以导致更高的升力，但功耗更高。