低雷诺数下襟翼缝隙几何参数对双元素翼帆推进特性的影响研究

Influence of slot geometry parameters of the flap on the propulsion characteristics of two-element wingsail at low Reynolds number

为了研究双元素翼帆在低雷诺数下的失速机理和气动特性,本文采用雷诺平均N-S方程在定常和非定常工况下对双元素翼帆模型进行数值仿真计算。结果表明,增大双元素翼帆的襟翼偏转角时,最大失速角减小,而最大升力系数同时受到缝隙相对宽度的影响,随缝隙相对宽度的增加先增大后减小,且缝隙相对宽度对最大升力系数大小和速度流场的影响要大于襟翼偏转角,襟翼偏转角的选择需保证缝隙射流足够补充主翼尾流因边界层分离引起的能量损失。增加缝隙相对宽度时,主翼尾流和襟翼吸力面先后出现了低速及回流现象,而缝隙相对宽度过小时绕流主翼尾缘的流体会减少,最大升力系数较低,因此缝隙相对宽度和襟翼偏转角共同影响着双元素翼帆的气动特性。

In order to study the stall mechanism and aerodynamic characteristics of the two-element wingsail at low Reynolds number,the Reynolds averaged N-S equation was used to simulate the two-element wingsail model under steady and unsteady conditions.The results show that the maximum stall angle will decrease when the flap deflection angle of the two-element wingsail increases.The maximum lift coefficient is affected by the relative width of the slot at the same time.With the increase of the relative slot width,the maximum lift coefficient will increase firstly and then decrease.And the influence of the relative width of the slot on the maximum lift coefficient and the velocity field is greater than that of the flap deflection angle.The choice of flap deflection angle needs to ensure that the slot jet is sufficient enough to supplement the energy loss caused by the separation of boundary layer in the wake of main wing.When the relative slot width increases,the low speed and reflux phenomenon appear successively in the main wing wake and the flap suction surface.When the relative slot width is too small,the flow around the trailing edge of the main wing will decrease and the maximum lift coefficient will be low.So the relative slot width and flap deflection angle together affect the aerodynamic characteristics of the two-element wingsail.