Experimental Validation of a Cascade Response Function for Fan Broadband Noise Predictions

摘要

The present paper is aimed at assessing an analytical prediction model for the broadband noise produced by the impingement of turbulence on a cascade, using a dedicated experiment. The model is a strip-theory approach based on a previously published formulation of the unsteady blade loading for a rectilinear cascade. The experimental setup is made of a single stationary cascade of vanes mounted downstream of a turbulence grid in an annular duct, at the exit of an open-jet anechoic wind tunnel. The statistical parameters of the turbulence measured with hot-wire anemometry are used as input data in the model. The in-duct predicted downstream acoustic power is compared with the measured power obtained from the far-field acoustic pressure. Measured and predicted variations of the acoustic power with the number of vanes of the cascade and with the turbulence intensity are found to be in good agreement. It is concluded that the analytical approach succeeds in highlighting three-dimensional effects and is promising for further comparisons in more complex annular configurations.