The aerodynamic noise with broadband low frequency generated from a multi-blade fan has been investigated by experimental and numerical analyses. In the experiment analysis, static pressure fluctuations on the scroll side-wall of the multi-blade fan were measured by high response pressure transducers, and their frequency characteristics were analyzed by fast Fourier transform. In the numerical analysis, internal flow phenomena in the scroll were investigated by Reynolds-averaged Navier-Stokes (RANS) simulations. It is found that the noise with broadband low frequency is generated by the interference between flows with high turbulent kinetic energy and the scroll side-wall.
