This work has refined and generalized a class of analytical methods for airframe noise prediction, providing a better understanding of the physical mechanisms of sound generation and propagation due to boundary-layer turbulence scattering at the edge of an aerodynamic profile. These methods are matured to be embedded in the early stages of the design cycle, often automated with optimisation algorithms, providing an accurate and low-computational-cost noise estimate.
In addition, this work provide an unprecedented database (available online) to study trailing edge noise sources with refined resolution of the near field turbulent flow. A detailed characterization of the surface pressure fluctuations provides an accurate input for possible analytical approaches, thus improve the far field predictions of noise creates by airfoils relevant to a CROR blade. The flow is computed for multiple values of Mach number, Reynolds number and angles of attack. In these simulations, a large set of probes is located around the geometry and these data will be proposed to the aeroacoustic/aerodynamic community.
Moreover, advanced methods have been developed to allow the use of Large Eddy Simulation in the context of reduced computational domain (through the use of phase-lagged boundary condition). The phase-lagged LES approach has been applied successfully to two complex configurations (CROR and FAN/OGV) showing that this approach can be used to predict acoustic data. It is a clear avantage to allow the use of high-fidelity CFD Methods for rotating machine in industry (The CPU cost is greatly reduced, it depends on the number of blades so we can expect a reduction of CPU time between 10 and 20).
