Turbine noise generation and suppression

An analytical method for the prediction of turbine generated noise is discussed. The method links the duct acoustic modes with the turbomachinery aerodynamics. The results of the analysis are compared with turbine component and engine results. Component data on the effects of the variation of axial spacing between blade rows on turbine aerodynamics and acoustics are presented. The results of an experimental evaluation of the relative importance of turbine noise on highly suppressed bypass turbofans are discussed. The development of high temperature acoustic treatment and its application to high bypass turbofans are presented.