The most prominent ambition was to achieve ‘low-noise design capabilities’, suitable for under-wing and rear-fuselage mounted engine installations. Hence, the goal was to demonstrate noise reduction due to wing-trailing-edge modifications and/or nozzle-based technologies such as jet vectoring, leading to their introduction into real-aircraft design.
In addition to high-fidelity simulation tools, a further ambition was to develop a low-cost simulation methodology with turn-over/wall-clock times at least three orders of magnitude faster than scale-resolving simulation.
It must be said that the goal of "low-noise design capabilities" turned out as a goal too far beyond the present capabilities.
The second item was an advanced experimental-numerical interaction and physical understanding, leading to the validation of low-noise technologies on different aircraft platforms with the potential to reduce community noise and to eliminate noise risks associated with future installation concepts and more efficient engines. This combined high-tech experimental methods with accurate numerical simulations to steer the development of noise reduction technologies.
Going beyond the state of the art meant to develop numerical multi-physics (CFD-CAA) methods enabling the integration of acoustic restraints early in the design process of new engines and configuration concepts (Design-to-noise). The use of turbulence-resolving simulations within DJINN advanced the understanding of complex noise source phenomena in general and led to favorable innovative noise-reduction technologies. Further progress has been achieved for shortening wall-clock times for CFD simulations by highly scalable codes The proof of concept is that GPU-based HRLMs resulted in more than 5 times faster computations. As said above, DJINN moved from large-scale testing to HiFi-CFD for higher-TRL demonstration.
Based on the information given above, the potential impacts, concerning the ‘Flightpath 2050’ goals, with CO2 emissions per passenger kilometer to be reduced by 75%, NOx by 90%, and perceived noise by 65% by 2050, relative to the year 2000, have been at least partially met. The most prominent ones are:
1. Significantly reduced A/C design cycle costs and time by improved numerical simulation tools.
2. Established and validated new NRT (noise reduction) technologies as a basis for noise-reduction technologies on both the engine and airframe sides.
3. Exploitation and technology transfer of high-fidelity methods and associated simulation processes to the OEM partners.
4. Strengthening competitiveness and growth of companies by providing (more) reliable CFD approaches.
5. Newmarket opportunities by making complex industrial simulations feasible and reducing design cycles and costs.
6. Routinely run HRLM/LES simulations of a complete aircraft in landing configuration for aero-acoustic applications with short turnaround times.
