Acoustic Radiation from High-Speed Turbulent Boundary Layers in a Tunnel-like Environment

at wall in an unconned setting. The DNS data shows that the acoustic uctuations dominate in the core region of the channel. The acoustic radiation from the two dierent channel walls superimposes with each other, resulting in an intensity of the acoustic uctuations approximately twice of that radiated from a single wall. The simulation is consistent with the observations by Laufer 1 who found that the acoustic uctuations radiated from dierent tunnel walls can be superimposed and the intensity of pressure uctuations in the core region of the tunnel test section is approximately equal to that radiated from a single tunnel-wall boundary layer multiplied by the number of radiating boundary layers.