大型客机缝翼滑轨系统气动噪声数值研究

采用非定常DDES方法研究了缝翼滑轨系统的时均流动特性和瞬态流动特性，并进一步采用FW-H方法对其远场气动噪声特性进行了评估分析。计算结果表明：1)相比无轨无舱构型，有轨无舱构型在滑轨根部上方出现了流场强脉动区。有轨有舱构型则进一步在滑轨舱内和主翼上翼面出现了更大的流场强脉动区；2)滑轨周围出现了类似方柱绕流的弦向涡对结构，并沿着机翼弦向不断扩张，而后受到滑轨舱空腔壁面的限制和挤压，最终破碎为大量的小涡并耗散消失；3)在展向对称面上，无轨无舱构型接近于典型的偶极子噪声；有轨无舱构型也接近于偶极子噪声，其主轴方向稍沿顺时针转动；有轨有舱构型则表现出非对称性；4)在270°方位角，滑轨和滑轨舱带来的总声压级增量分别为7 dB左右和2 dB左右。

Numerical study on aeroacoustics of slat system of airliner

The unsteady DDES method was used to study the time averaged flow characteristics and transient flow characteristics of slat system, and the far-field aerodynamic noise characteristics of slat system were evaluated and analyzed by FW-H method. The results show that: 1) In the with track no cavity configuration, there is a strong pulsation region of the flow field above the root of the track. In the with track with cavity configuration, there is a larger strong pulsation region of the flow field in the cavity and on the upper wing surface of the main wing; 2) A chordwise vortex pair structure similar to the flow around a square column appears around the track, which expands along the wing chord, and then is limited and squeezed by the wall of the cavity, and finally breaks into a large number of small vortices and dissipates; 3) In the spanwise symmetric plane, the no track no cavity configuration is similar to a typical dipole noise source; the with track no cavity configuration is also similar to a dipole source, while the principal axis rotates clockwise a little; the with track with cavity configuration shows asymmetry; 4) At 270° azimuth, the overall sound pressure level increment brought by the track and its cavity is about 7 dB and 2 dB respectively.