Conceptual study of micro-tab device in airframe noise reduction: (I) 2D computation

A two-dimensional numerical study was performed to investigate the acoustic effects of micro-tab device on airframe noise reduction. As the noise generated by leading-edge slat and trailing-edge flap rise with their increased deflection angles, it is possible to mitigate such high-lift noise by using reduced settings without sacrificing the aerodynamic performance during approach. In this paper, micro-tab device attached to the pressure side of the flap surface is envisioned as a mean to achieve this goal. Hybrid method involving Computational Fluid Dynamics and acoustic analogy was used to predict the far-field noise spectrum. Results illustrate that the micro-tab device with reduced deflection angles of the high-lift settings provides lower noise signature at far-field positions, comparing to the baseline configuration, while the aerodynamic performance is maintained. In addition, two parametric studies which investigated the effects of micro-tab location and micro-tab height on acoustic spectra were also included.