Sound Radiation from a Bypass Duct with Bifurcations

摘要

The influence of bifurcations in an aeroengine bypass duct on noise radiation was investigated through high-order-accurate three-dimensional numerical simulations. The physical process was described by a set of acoustic perturbation equations. Four bifurcation arrangements with an airfoil cross section were regularly placed in circumferential direction. Results were compared with those of an axisymmetric duct case without the installation of bifurcations. Both near-field propagation and far-field radiation were studied to show that the bifurcations scatter acoustic modes and redirect sound propagation levels. Compared to the axisymmetric duct case, there are a couple of decibel increases in sound pressure level on some angles due to the installation of bifurcations. The method is also applicable to other configurations with different bifurcations and modes.