{"title":"Tonal Noise Transmission through a Non-Axisymmetric Turbine OGV with Separated Flow: Prediction and Measurements","authors":"J. R. Aparicio, A. Serrano","doi":"10.2514/6.2018-3914","DOIUrl":"https://doi.org/10.2514/6.2018-3914","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115804198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonlinear Acoustics in a Non-Parallel Boundary Layer over an Acoustic Lining","authors":"Owen Petrie, E. Brambley","doi":"10.2514/6.2018-3607","DOIUrl":"https://doi.org/10.2514/6.2018-3607","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124953558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The National Aeronautics and Space Administration (NASA) Acoustic Research Measurements (ARM) project was established to evaluate via flight tests the noise reduction benefits of the Adaptive Compliant Trailing Edge (ACTE) technology along with various main landing gear noise reduction concepts. The ACTE replaces the original Fowler flaps on the NASA SubsoniC Research Aircraft Testbed (SCRAT), thus creating a seamless trailing edge that provides significant noise abatement benefits. The various main landing gear noise reduction concepts are grouped under the LAnding Gear noisE Reduction (LAGER) task and consist of fairings placed on the main landing gear along with two separate treatments applied to the main landing gear wheel well cavities. This paper discusses the tasks necessary to prepare each of these technologies for the ARM flights. The LAGER hardware was taken from model-scale concepts tested in wind tunnels to flight hardware, which had to be cleared as airworthy for the ARM flights. The ACTE flaps were initially intended to be removed from the SCRAT prior to the start of the ARM project. Retaining the ACTE flaps on the aircraft for a longer period of time to support the ARM flights resulted in additional inspections and considerations since the ACTE flaps were flown longer and at certain flight conditions for longer periods of time than initially analyzed. The flight and ground operations required for the ARM tests required extensive coordination among multiple groups and organizations in order to be successful. This paper provides an overview of the hardware development, ground operations, and flight operations which went into acquiring the desired acoustic measurements. In general, the flights were successful and demonstrated the noise reduction benefits of the ACTE flaps, the LAGER gear fairings, and the LAGER gear cavity treatments.
{"title":"Flight and Ground Operations in Support of Airframe Noise Reduction Tests","authors":"E. Baumann, E. Waggoner","doi":"10.2514/6.2018-2970","DOIUrl":"https://doi.org/10.2514/6.2018-2970","url":null,"abstract":"The National Aeronautics and Space Administration (NASA) Acoustic Research Measurements (ARM) project was established to evaluate via flight tests the noise reduction benefits of the Adaptive Compliant Trailing Edge (ACTE) technology along with various main landing gear noise reduction concepts. The ACTE replaces the original Fowler flaps on the NASA SubsoniC Research Aircraft Testbed (SCRAT), thus creating a seamless trailing edge that provides significant noise abatement benefits. The various main landing gear noise reduction concepts are grouped under the LAnding Gear noisE Reduction (LAGER) task and consist of fairings placed on the main landing gear along with two separate treatments applied to the main landing gear wheel well cavities. This paper discusses the tasks necessary to prepare each of these technologies for the ARM flights. The LAGER hardware was taken from model-scale concepts tested in wind tunnels to flight hardware, which had to be cleared as airworthy for the ARM flights. The ACTE flaps were initially intended to be removed from the SCRAT prior to the start of the ARM project. Retaining the ACTE flaps on the aircraft for a longer period of time to support the ARM flights resulted in additional inspections and considerations since the ACTE flaps were flown longer and at certain flight conditions for longer periods of time than initially analyzed. The flight and ground operations required for the ARM tests required extensive coordination among multiple groups and organizations in order to be successful. This paper provides an overview of the hardware development, ground operations, and flight operations which went into acquiring the desired acoustic measurements. In general, the flights were successful and demonstrated the noise reduction benefits of the ACTE flaps, the LAGER gear fairings, and the LAGER gear cavity treatments.","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131508443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karl-Stéphane Rossignol, J. Delfs, M. Mößner, D. Gély, J. Bulté, F. Hutcheson
This paper presents the experimental results of a study conducted at DLR, ONERA and NASA on the shielding of sound by an NACA 0012 airfoil. The work presented was done in the context of the AVT-233 working group of the Science and Technology Organization (STO) of NATO. The experiments were conducted in the DLR Acoustic Wind Tunnel Braunschweig (AWB), the ONERA F2 tunnel and the NASA Quiet Flow Facility (QFF), with the goal of investigating facility-to-facility effects on the collected data. Two impulsive source concepts were used in the course of these experiments, DLR’s laser sound source and ONERA’s electric discharge source (SPARC). The collected data reveal that the different tunnel environments do not strongly affect the results obtained with either source. The laser sound source is found to deliver consistent results in all three wind tunnels, for the 7, 14 and 28 kHz octave bands at M=0.0 and M=0.16. In the highest octave band considered (56 kHz), the results are found to be very sensitive to the choice of operating parameters. The SPARC source also delivered consistent results in the low frequency range, in both the F2 tunnel and the AWB, for both Mach numbers tested. This joint effort has led to the development of a highly valuable database for the validation of shielding prediction tools.
{"title":"Experimental Investigations on Noise Shielding: Dependency on Reference Noise Source and Testing Environment","authors":"Karl-Stéphane Rossignol, J. Delfs, M. Mößner, D. Gély, J. Bulté, F. Hutcheson","doi":"10.2514/6.2018-2820","DOIUrl":"https://doi.org/10.2514/6.2018-2820","url":null,"abstract":"This paper presents the experimental results of a study conducted at DLR, ONERA and NASA on the shielding of sound by an NACA 0012 airfoil. The work presented was done in the context of the AVT-233 working group of the Science and Technology Organization (STO) of NATO. The experiments were conducted in the DLR Acoustic Wind Tunnel Braunschweig (AWB), the ONERA F2 tunnel and the NASA Quiet Flow Facility (QFF), with the goal of investigating facility-to-facility effects on the collected data. Two impulsive source concepts were used in the course of these experiments, DLR’s laser sound source and ONERA’s electric discharge source (SPARC). The collected data reveal that the different tunnel environments do not strongly affect the results obtained with either source. The laser sound source is found to deliver consistent results in all three wind tunnels, for the 7, 14 and 28 kHz octave bands at M=0.0 and M=0.16. In the highest octave band considered (56 kHz), the results are found to be very sensitive to the choice of operating parameters. The SPARC source also delivered consistent results in the low frequency range, in both the F2 tunnel and the AWB, for both Mach numbers tested. This joint effort has led to the development of a highly valuable database for the validation of shielding prediction tools.","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133744142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vaibhav Kumar, Shane V. Lympany, Gerhardus O. Loohuis, K. Ahuja
{"title":"Control of Acoustic Impedance of a Resonant Liner by Varying Orifice Geometry through Multi-Layer Sliding Perforates","authors":"Vaibhav Kumar, Shane V. Lympany, Gerhardus O. Loohuis, K. Ahuja","doi":"10.2514/6.2018-4191","DOIUrl":"https://doi.org/10.2514/6.2018-4191","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"570 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131887268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental and Numerical Study of Jet Noise Reduction for Supersonic Aircraft Using Variable Folding Nozzle Concept","authors":"J. Akatsuka, T. Ishii","doi":"10.2514/6.2018-3612","DOIUrl":"https://doi.org/10.2514/6.2018-3612","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132233320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Geyer, D. Moreau, J. Giesler, Philipp M Hall, E. Sarradj, C. Doolan
The flow around a wall-mounted finite airfoil with natural transition can lead to complex tonal characteristics in the corresponding aeroacoustic noise spectra. While many of the flow features and noise generating mechanisms are well understood, there are still open questions, for example regarding the influence of the airfoil shape. In the present paper, the influence of the thickness of a wall-mounted finite airfoil on the noise generation is examined experimentally. To this end, detailed measurements were performed on a NACA0012 airfoil and a NACA0018 airfoil in an open jet aeroacoustic wind tunnel at various flow speeds and angles of attack. This includes acoustic measurements with a planar microphone array as well as measurements of the surface pressure fluctuations using flush-mounted pressure capsules. In addition, surface flow visualization experiments were conducted on the NACA0012 airfoil. The results show that the thickness of the airfoil has a notable influence on the tonal noise generation, which is visible both in the sound pressure level spectra as well as in the wall pressure spectra. At small geometric angles of attack and high flow speeds, the thinner NACA0012 generates a strong tone with weaker side tones, whereas the NACA0018 generates a set of equispaced tones. At higher angles the NACA0012 does not radiate tonal noise, while the NACA0018 now generates this strong tone with weaker side tones.
{"title":"Measurement of the noise generated by wall-mounted airfoils of different thickness","authors":"T. Geyer, D. Moreau, J. Giesler, Philipp M Hall, E. Sarradj, C. Doolan","doi":"10.2514/6.2018-3796","DOIUrl":"https://doi.org/10.2514/6.2018-3796","url":null,"abstract":"The flow around a wall-mounted finite airfoil with natural transition can lead to complex tonal characteristics in the corresponding aeroacoustic noise spectra. While many of the flow features and noise generating mechanisms are well understood, there are still open questions, for example regarding the influence of the airfoil shape. In the present paper, the influence of the thickness of a wall-mounted finite airfoil on the noise generation is examined experimentally. To this end, detailed measurements were performed on a NACA0012 airfoil and a NACA0018 airfoil in an open jet aeroacoustic wind tunnel at various flow speeds and angles of attack. This includes acoustic measurements with a planar microphone array as well as measurements of the surface pressure fluctuations using flush-mounted pressure capsules. In addition, surface flow visualization experiments were conducted on the NACA0012 airfoil. The results show that the thickness of the airfoil has a notable influence on the tonal noise generation, which is visible both in the sound pressure level spectra as well as in the wall pressure spectra. At small geometric angles of attack and high flow speeds, the thinner NACA0012 generates a strong tone with weaker side tones, whereas the NACA0018 generates a set of equispaced tones. At higher angles the NACA0012 does not radiate tonal noise, while the NACA0018 now generates this strong tone with weaker side tones.","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117269217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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