The Synthetic Jet (SJ) control on the propulsion behavior of a foil in plunge-pitch motion is examined in this work by numerical simulations. An elliptic foil with ratio of 8 performs the plunge and pitch motions synchronously. A pair of SJs with the same frequency and strength is integrated into the upper and lower surfaces of the foil. As a result, the local flow field around the foil could be obviously modified by the SJs. At the Reynolds number of 200, the effects of the inclined angle between the jet direction and the chord line, the phase angle between the SJs and the flapping motion as well as the location of SJ on the propulsion performance are systematically investigated. Compared with the pure plunging and pitching foil, it is indicated that the enhancement of mean thrust and propulsive efficiency can be obtained by the SJs with suitable working parameters. Based on the numerical analysis, it is found that the jet flow on the foil surfaces, which changes the local pressure distribution to increase the pressure difference between upper and lower surfaces, can benefit the propulsion behavior of the flapping foil.

中文翻译：

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斜桨运动中铝箔推进性能的合成射流控制

在这项工作中，通过数值模拟研究了箔片在俯仰-俯仰运动中的推进行为的合成射流（SJ）控制。比率为8的椭圆箔同时执行插入运动和俯仰运动。将一对具有相同频率和强度的SJ集成到箔的上表面和下表面。结果，SJ可以明显改变箔片周围的局部流场。在雷诺数为200的情况下，系统地研究了射流方向与弦线之间的倾斜角，SJ之间的相位角和拍打运动以及SJ的位置对推进性能的影响。与纯浸水和俯仰箔相比，结果表明，具有合适工作参数的SJ可以提高平均推力和推进效率。基于数值分析，发现箔表面上的喷射流改变了局部压力分布，从而增大了上，下表面之间的压力差，可以改善拍打箔的推进性能。