Periodic Reporting for period 2 - DJINN (Decrease Jet-Installation Noise)
Okres sprawozdawczy: 2021-12-01 do 2023-11-30
External aircraft noise has become an important political issue. As an example, the noise radiation of a turbofan is substantially increased when installed under the wing of an aircraft. Hence, the installation noise sources in the low-frequency range with Strouhal numbers between 0.2 and 2 increase the noise emission by up to 14 dB for an observer position directly below the aircraft, see attached Bild1.jpg (Frequency noise spectra for isolated and installed UHBR nozzle (Courtesy: CFD-Berlin)). The problem of Strouhal number restrictions has been overcome as being part of the DJINN project. Although not all partners working on this issue were completely successful (only partial improvements have been achieved), some partners were able to get up to St=10, see attached Fig.14a-2.jpeg (Improvement of predictions with LD2 (Courtesy CFD-Berlin)).
The goal of the DJINN project was to push noise-reduction technologies to a Technology Readiness Level (TRL) between 4 and 5. Indeed, the results and new/advanced CFD methods obtained in the DJINN project led to improved simulation platforms by the partners. All in all, the industrial partners agreed on the situation to have reached a TRL between 4-5.
The DJINN project offered a significant step-change and improvement for ensuring a favourable environment.
The following summarised overall objectives have been met:
1. Increasing the frequency range of simulations up to Strouhal numbers of 10, whilst maintaining affordability and ability to capture the complex geometries representing the two aircraft configurations selected.
2. Predicting under-wing jet-airframe interaction noise to within 1 dB accuracy.
3. Demonstration of a reduction of jet-airframe interaction noise peak level at low frequencies by 5 dB.
4. Reducing the turn-around time of high-order (CFD) approaches by a factor of 5, using h-p refinement techniques for approaches such as Spectral Difference Methods (SDM) (mesh + simulation + post-processing).
5. Involvement of GPU computer architectures to increase the turn-around time even more.
6. Evaluating innovative high-fidelity simulation-method components (accelerators, alternatives to FWH, improved numerical schemes) and reducing turn-around times significantly – in the case of GPU usage by an additional (estimated) factor greater than 5.
7. Reducing design times and costs by 25% compared to large-scale testing.
The goal of the DJINN project was to push noise-reduction technologies to a Technology Readiness Level (TRL) between 4 and 5. Indeed, the results and new/advanced CFD methods obtained in the DJINN project led to improved simulation platforms by the partners. All in all, the industrial partners agreed on the situation to have reached a TRL between 4-5.
The DJINN project offered a significant step-change and improvement for ensuring a favourable environment.
The following summarised overall objectives have been met:
1. Increasing the frequency range of simulations up to Strouhal numbers of 10, whilst maintaining affordability and ability to capture the complex geometries representing the two aircraft configurations selected.
2. Predicting under-wing jet-airframe interaction noise to within 1 dB accuracy.
3. Demonstration of a reduction of jet-airframe interaction noise peak level at low frequencies by 5 dB.
4. Reducing the turn-around time of high-order (CFD) approaches by a factor of 5, using h-p refinement techniques for approaches such as Spectral Difference Methods (SDM) (mesh + simulation + post-processing).
5. Involvement of GPU computer architectures to increase the turn-around time even more.
6. Evaluating innovative high-fidelity simulation-method components (accelerators, alternatives to FWH, improved numerical schemes) and reducing turn-around times significantly – in the case of GPU usage by an additional (estimated) factor greater than 5.
7. Reducing design times and costs by 25% compared to large-scale testing.
Work performed in the DJINN project (starting 1 June 2020) is exhibited in the final technical report. This report contains all relevant achievements.
In addition to that, the so-called Quarterly Progress Report regarding the situation until the end of the DJINN project has been added to the final technical report to make the work effort more transparent.
The main results are explained in the section below, and the main exploitation and dissemination are summarised as such:
1. All results obtained will be exploited by the partners according to their needs. This holds in particular for the wind tunnel test case date to which the industry partners signed an agreement to be able to use all results n future endeavours.
2. Within two open international conferences research results have been exchanged with people outside the DJINN project, enabling exploitation of data and results.
3. Two generic test cases have been identified for an open download vis the DJINN website. WIth 15 downloads in total, further actions are foreseen (conferences, workshops, running cases in their own environment).
4. Dissemination was forced by the DJINN website. Moreover, the DJINN project was offered dissemination by EUROTURB, ENODISE, ERCOFTAC, ISimQ, ECCOMAS, PULSAR, and VKI.
5. A special dissemination action was initiated by ADJACENT, OpenaccessGovenrment, and paid by the coordinator. This included:
- A publication: https://edition.pagesuite-professional.co.uk/html5/reader/production/default.aspx?pubname=&edid=eaaa2691-f2e2-4ecd-9e5e-f2985210b663(odnośnik otworzy się w nowym oknie)
- Banner on OAG website announcing the two DJINN conferences plus a press release.
In addition to that, the so-called Quarterly Progress Report regarding the situation until the end of the DJINN project has been added to the final technical report to make the work effort more transparent.
The main results are explained in the section below, and the main exploitation and dissemination are summarised as such:
1. All results obtained will be exploited by the partners according to their needs. This holds in particular for the wind tunnel test case date to which the industry partners signed an agreement to be able to use all results n future endeavours.
2. Within two open international conferences research results have been exchanged with people outside the DJINN project, enabling exploitation of data and results.
3. Two generic test cases have been identified for an open download vis the DJINN website. WIth 15 downloads in total, further actions are foreseen (conferences, workshops, running cases in their own environment).
4. Dissemination was forced by the DJINN website. Moreover, the DJINN project was offered dissemination by EUROTURB, ENODISE, ERCOFTAC, ISimQ, ECCOMAS, PULSAR, and VKI.
5. A special dissemination action was initiated by ADJACENT, OpenaccessGovenrment, and paid by the coordinator. This included:
- A publication: https://edition.pagesuite-professional.co.uk/html5/reader/production/default.aspx?pubname=&edid=eaaa2691-f2e2-4ecd-9e5e-f2985210b663(odnośnik otworzy się w nowym oknie)
- Banner on OAG website announcing the two DJINN conferences plus a press release.
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.
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.