Sound propagation in multi-stage axial flow turbomachines

Numerical simulation of multistage turbine sound generation and propagation

“…While another tested method of sound propagation [33,34], the four pole theory [13,14], is exact under certain circumstances (e.g. no mode conversion), the beetle method leads to better results when any reflection of waves can be neglected.…”

“…mode-trapping [11] or sum and difference tones due to scattering. Several analytical or numerical methods for calculating sound propagation through multiple cascades have been developed [2,10,12,13]. Some of these mostly analytical methods are restricted to two-dimensional flows through flat plates.…”

“…Here, Lin3D was used for noise generation computations and TR-LOSS for the sound propagation, based on the four pole theory coupling 2D flat plate calculations [13,14]. This method should preferably be used for compressors where the 3D geometry of blades and vanes is very close to 2D flat plates.…”