Aeroacoustic Study of Strut Braced Ultra-High Aspect Ratio Wings

To enhance aerodynamic efficiency, reduce fuel consumption, and minimize emissions in the next-generation of air transport, a strut-braced ultra-high aspect ratio wing (UHARW) is a promising solution. However, the addition of a bracing strut may have aeroacoustic implications. This paper assesses the noise generated by a strut-braced UHARW, focusing on two primary source types. The first is dipole noise, and the second is trailing-edge noise from both the main wing and bracing strut. Wall-modeled large-eddy simulations and the Ffowcs-Williams and Hawkings (FWH) equation are used to calculate the dipole noise. The results indicate a noise increase of approximately 3.5 dB over a wide frequency range due to the bracing strut at the local spanwise section where it is located. The trailing-edge noise of the main wing and strut is estimated using the trailing-edge noise prediction model of Brooks, Pope, and Marcolini. The noise of a full-span, realistic UHARW wing is estimated using a model based on the time domain FWH equations and spanwise strip theory. It is found that the addition of the bracing strut increases the maximum tone-corrected perceived noise level by approximately 0.8 PNdB at the wing source level, without considering other airframe or engine noise sources.