Abstract

One of the great advances in aircraft efficiency has been the development of the open rotor engine. This incorporates two huge, counter-rotating propellers which lie outside the nacelle. Unfortunately, these are incredibly noisy and a major design issue exists in bringing the noise down to acceptable levels. Our work considers one particular aspect of this problem, termed unsteady distortion noise, which arises from the ‘slicing’ of turbulent eddies from the atmosphere as they pass through the rotors, producing unsteady forces on the blades.

This work aims to address questions including: the reliability of ground-based testing as a noise prediction tool; the influence of asymmetries, such as the presence of the fuselage on one side of the rotors; and the effect an upstream engine exhaust may have. This talk is very much of work-in-progress, as I enter my second year of a PhD in DAMTP , and should be pretty accessible to most CUED PhD students.