1. Development of a computational tool for modelling jet noise
2. Assessment of existing high-fidelity data: databases were exhaustively analysed to assess suitability for use as input to computational tool (1). Analysis identified hitherto unknown sources of error. Solutions were developed to enable error mitigation for existing data, and novel error-mitigation strategies for the generation of new data.
3. New theoretical guidelines: computational tool (1) was elaborated using state-of-the-art techniques. DARETOMODEL identified a hitherto unknown theoretical ambiguity implicit in these techniques. A correction was identified that both removes the ambiguity and shows how it may be beneficially exploited.
4. Combining (1), (2) & (3), best-practice guidelines were established for physics-based jet-noise modelling.
5. A novel data-analysis tool, RESPOD (Resolvent-based Extended Spectral Proper Orthogonal Decomposition), was developed for eduction of turbulence structure responsable for an observable of interest (e.g. drag, stability, noise,...).
6. Use of RESPOD to identify turbulence structure responsible for jet noise.
7. Construction, thanks to (6), of semi-empirical model for noise-producing turbulence structure.
8. Use of (7) to perform jet-noise prediction.
9. Evaluation of robustness of (7).
10. Development of second empirical modelling strategy that bypasses turbulence structure.
11. Transfer of tools (points 1, 7 & 10) and associated knowledge (points 2, 3, 4, 5, 6, 9) to Airbus.
12. Implementation of jet-noise modelling tool in industry environment, using industry tools.
13. Evaluation of robustness of the modelling tool in an industry environment.
14. Design of experiment to assess effect of flight on jets and their sound.
15. Velocity measurements of jets with flight stream.
16. Acoustic measurements of jets with flight stream.
17. Acoustic measurements of jet and wing, in static and flight conditions.
18. High-fidelity numerical simulation of the jets in flight.
19. Post-processing/analysis of new databases to assess effect of flight on jet.
20. Identification of effect of flight on flow structures.
21. Modelling the effect of flight on flow structures.
Results, exploitation and dissemination:
1. The main result of the project is a tool for predicting jet noise using input data from standard industry tools. The tool was developed and validated using data from experiments and high-fidelity numerical simulation. Signal-processing tools were elaborated for mining the data. Databases were used to guide/inform the jet-noise prediction tool, tailored and tested for robustness to changes in operating condition and errors in data. The prediction tool was transferred to an industry environment. Airbus engineers learned to use the tool; it was integrated into their suite of modelling tools; it was validated in the industry environment and shown to provide robust noise prediction with minimal input data from standard, fast-return, industry CFD.
2. Dissemination of results, in addition to the transfer of knowledge and tools to Airbus, took the form of publications in leading journals. 5 journal publications are in print; 4 are submitted or in preparation. Expected final output is 9 journal papers. Results were also presented at the 2022 AIAA/CEAS Aeroacoustics Conference; at the ICTAM conference in 2021; at the Euromech Colloquium, in Poitiers, 2021.
3. A Euromech Colloquium was organised in Poitiers 2021. DARETOMODEL results were showcased. A 33-page book of abstracts was produced, as was a 4-page scientific report.
4. DARETOMODEL databases will continue to guide future jet-noise research.
