Output details

An analytic Green's function for a lined circular duct containing uniform mean flow

Significance of output:

One of the most effective means of reducing aircraft noise is to absorb the internally-generated engine noise by acoustically lining the duct walls. However the acoustic performance of linings can be compromised by features such as hard joins (‘splices’). To predict these effects for Rolls-Royce, and reduce the risk of failing engine noise certification, requires the Green’s function, the radiation due to a point source. This function was not previously available for an acoustically lined duct containing mean flow but the function has been derived in this paper, providing the means to solve the liner-splice-scattering problem in a related paper.