Computational study of flow incidence effects on the aeroacoustics of low blade-tip Mach number propellers

This paper presents a computational study of flow incidence effects on the aeroacoustics propeller operating at low blade-tip Mach numbers. The numerical solution is obtained by using Lattice-Boltzmann/Very Large Eddy Simulation method, while far-field noise computed through Ffowcs-Williams & Hawkings' acoustic analogy applied surface. presence an angular inflow leads to: (i) radiation tonal loading along axis; (ii) increment/reduction sound pressure level in region from/to which tilted away/towards. However, contrarily to propellers high numbers, directivity change found be governed only rise periodic unsteady loadings, with modulation strength sources blade, associated variation observer-source relative number (in blade reference frame), being negligible. Finally, thickness and turbulent boundary-layer trailing-edge did not show significant due yaw angle change.