Recently, the aircraft noise becomes more important due to military and commercial demands. And the majority of the aircraft noise is generated by the fan and compressor, because the most of the modern aircraft have high bypass ratio engines. Therefore, to predict aircraft interior/exterior noise precisely, it is necessary to calculate fan and compressor noise.
In engine inlet, a acoustic field is strongly coupled with a flow field. So, if the Mach number arrives to some degree, we cannot use linear wave equation anymore, due to nonlinear effect. Therefore, in this thesis, a nonlinear Euler equation is used in order to calculate the acoustic field and the flow field in the inlet at the same time.
Because the acoustic property has much smaller amplitude compared with the flow field, we must use high resolution scheme. In this thesis, optimized compact scheme, that is one of new CAA(computational aeroacoustics) techniques, is applied to the general problem of aircraft engine inlet. And, conformal mapping is used for the grid generation, which makes the grid with good orthogonality and metric distribution.
To validate the developed code, the acoustic fields driven by baffle and monopole source are computed and compared with exact solutions. Finally, the fan modelling of Tyler & Sofrin is applied to the real JT15D engine, and the propagation patterns of each mode are presented.
