Broadband noise prediction models and measurements of tip leakage flows

Further experimental analysis of a tip leakage flow and of its associated broadband noise generation is investigated. Based on simultaneous 2 D LDA, unsteady wall pressure and far field measurements, a low frequency domain in the far field spectrum is related to the tip leakage vortex and its interaction with the blade t ip. A study on the convection of structures detected at the suction side edge is presented. An attempt to model the low frequency broadband noise generation is described. The underlying theory, based on linearised unsteady aerodynamics, is presented along with firs t results. An approach for broadband noise prediction in a higher frequency range is als o described.