Prediction of Noise from Turbulent Boundary Layers with Suction

Prediction of Noise from Turbulent Boundary Layers with Suction

Suction is used to control boundary layers on wings, inlets, wind tunnels, and other aerospace devices. Designing suction mechanisms to minimize noise generation is critical to reduce aeroacoustic loading and to conduct low-noise measurements. A semi-empirical acoustic analogy is used to predict the noise from the boundary layer when suction is present. The model depends on local turbulent boundary layer statistics. These statistics are calculated via a steady Reynolds-averaged Navier-Stokes computational fluid dynamics solver. Acoustic predictions are conducted at three subsonic Mach numbers over a flat plate without a pressure gradient. To study the effect of suction, a single thin port is placed at the wall with constant back pressure. At each Mach number, the change of sound pressure level with frequency is compared to a corresponding case with no suction. We observe that the presence of suction leads to increased noise at low Mach numbers and decreased noise at higher Mach numbers.