Numerical study on noise reduction of ground-effect wing with serrated trailing edge

• The object of the study is the wing trailing edge noise of an innovative groundeffect vehicle, aero-train. • This study is a novel approach in trailing edge noise reduction by applying the serrated trailing edge designs under high-speed and near-wall conditions. • This study uses the compressible LES/Möhring method for numerical simulation, and considering the reflection and diffraction of noise from the wall in the semi-free space. • The analysis of the acoustic results in this study is based on the details of the transient boundary layer flow detail. This study proposes a passive bionic noise reduction strategy using serrated trailing edge (TE) designs to be applied to the aero-train's ground-effect wing. The aim is to mitigate TE noise by suppressing the tail vortex under high-speed and near-wall conditions. Three different serrated TE designs were numerically investigated via large eddy simulation, combined with Möhring acoustic analogy theory under Ma = 0.3 to reveal their noise reduction effects. The noise reduction mechanism was analyzed from the perspective of the flow characteristics in the TE boundary layer. The results indicate that all serrated TE designs achieve noise reduction, with the TE2 exhibiting superior performance. This outcome is linked to the ability of serrated TE designs to moderate boundary layer airflow separation and backpressure gradients, facilitating smoother transitions and lessening wake vortex intensity, thereby reducing turbulence-induced noise. Designs featuring wider serration gaps and sharper edges further enhance noise attenuation.