COMPUTATIONAL MODELLING OF ACOUSTIC SCATTERING FROM A CYLINDRICAL DUCT WITH A ROTOR INTO UNIFORM MEAN FLOW

Abstract. The paper presents a computational study of acoustic scattering from a cylin-drical duct into uniform flow. The sound source is a fan inside the duct responsible for generating a spinning acoustic mode. The sound pressure scattering behaviour as func-tion of the fan tip speed and mean flow velocity, as well as the acoustic modes propagation inside the duct are investigated. A direct collocation boundary integral equation method (BIEM) is employed for calculating the acoustic propagation in incompressible and com-pressible flows. The BIEM is based on the equations of linearised acoustics with uniform inflow and has the advantage of taking into account wake effects.