{"title":"Correction: An Analytic Solution for Gust-Cascade Interaction Noise Including Effects of Realistic Aerofoil Geometry: Inter-Blade Region","authors":"Peter J. Baddoo, Lorna J. Ayton","doi":"10.2514/6.2018-2957.C1","DOIUrl":"https://doi.org/10.2514/6.2018-2957.C1","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124941234","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}
G. Yakhina, M. Roger, A. Finez, Valentin Baron, S. Moreau, Justine Giez
The present paper describes a post-processing methodology of microphone-array results for accurate source localization and separation. A deconvolution method CIRA is used to extract quantitative spectral results for multiple noise sources identified on a wallmounted, finite-span swept and cambered airfoil tested in an open-jet aeroacoustic facility. This allows understanding the contribution of each source in the noise generation process. The total sound pressure level is reconstructed from the individual spectra of each noise source and extrapolated in the far field to be compared with a single-microphone spectrum. The Bayesian algorithm is used to improve the comparison between reconstructed and experimental spectra as it takes into account the coherent nature of the sources. Remaining discrepancies motivate a re-examination of the assumptions made in the post-processing, aimed at making the spectral characterization of extracted sources more accurate. For this, analytical models of the source mechanisms and of their spanwise correlation are proposed as a tool to define future improvements.
{"title":"Correction: Broadband Airfoil-Noise Source Localization by Microphone Arrays and Modeling of a Swept Free-Tip Blade","authors":"G. Yakhina, M. Roger, A. Finez, Valentin Baron, S. Moreau, Justine Giez","doi":"10.2514/6.2018-3935.C1","DOIUrl":"https://doi.org/10.2514/6.2018-3935.C1","url":null,"abstract":"The present paper describes a post-processing methodology of microphone-array results for accurate source localization and separation. A deconvolution method CIRA is used to extract quantitative spectral results for multiple noise sources identified on a wallmounted, finite-span swept and cambered airfoil tested in an open-jet aeroacoustic facility. This allows understanding the contribution of each source in the noise generation process. The total sound pressure level is reconstructed from the individual spectra of each noise source and extrapolated in the far field to be compared with a single-microphone spectrum. The Bayesian algorithm is used to improve the comparison between reconstructed and experimental spectra as it takes into account the coherent nature of the sources. Remaining discrepancies motivate a re-examination of the assumptions made in the post-processing, aimed at making the spectral characterization of extracted sources more accurate. For this, analytical models of the source mechanisms and of their spanwise correlation are proposed as a tool to define future improvements.","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126582102","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}
James B. Lewis, R. Mankbadi, V. Golubev, L. Nguyen, Saman Salehian
{"title":"Correction: A Validation of High-Order Compact ILES Code for Trailing-Edge Noise at High Reynolds Numbers","authors":"James B. Lewis, R. Mankbadi, V. Golubev, L. Nguyen, Saman Salehian","doi":"10.2514/6.2018-3128.C1","DOIUrl":"https://doi.org/10.2514/6.2018-3128.C1","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130928045","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}
Patricio A. Ravetta, M. Khorrami, B. Konig, E. Fares
{"title":"Correction: Analysis of Simulated and Experimental Noise Sources of Boeing 777 Main Gear Model via CLEAN in 3D","authors":"Patricio A. Ravetta, M. Khorrami, B. Konig, E. Fares","doi":"10.2514/6.2018-3470.C1","DOIUrl":"https://doi.org/10.2514/6.2018-3470.C1","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125460852","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":"Correction: A Hybrid Computational Aeroacoustic Method For Low Speed Flows","authors":"A. Tosh, M. Caraeni, D. Caraeni","doi":"10.2514/6.2018-4096.C1","DOIUrl":"https://doi.org/10.2514/6.2018-4096.C1","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123305507","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. Ishii, K. Nagai, H. Oinuma, T. Oishi, R. Kagaya, Yutaka Ishii
{"title":"Correction: Noise Measurement of Small Turbofan Engine with Notched Nozzle for Jet Noise Reduction","authors":"T. Ishii, K. Nagai, H. Oinuma, T. Oishi, R. Kagaya, Yutaka Ishii","doi":"10.2514/6.2018-3611.C1","DOIUrl":"https://doi.org/10.2514/6.2018-3611.C1","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134390133","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}
N. A. Balantrapu, Russell J. Repasky, Liselle A. Joseph, W. Devenport
{"title":"Correction: The Dynamic Response of a Pinhole Microphone under Flows of Varying Shear Stress","authors":"N. A. Balantrapu, Russell J. Repasky, Liselle A. Joseph, W. Devenport","doi":"10.2514/6.2018-3933.C1","DOIUrl":"https://doi.org/10.2514/6.2018-3933.C1","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114218382","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":"Correction: A model for the sound generated by entropy disturbances interacting with isolated blades","authors":"J. Inigo, I. Duran, A. Morgans","doi":"10.2514/6.2018-2958.C1","DOIUrl":"https://doi.org/10.2514/6.2018-2958.C1","url":null,"abstract":"","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123524940","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}
S. Grace, Ankush Gupta, Ignacio Gonzalez-Martino, D. Casalino
Modern computational capabilities make simulations of complicated flow fields such as those in the fan stage of a turbofan engine possible. In particular, time resolved simulations are presenting new opportunities for studying the disturbances responsible for the broadband noise created by the fan stage. A preliminary quantitative analysis of the simulated flow field in the gap between the fan and fan exit guide vane (FEGV) computed with the Lattice Boltzmann based software PowerFLOW is presented. The study compares the simulated flow with experimental measurements to assess the mean flow, the turbulence intensity, the turbulence length scale and the turbulence dissipation rate. The mean wake is shown to be more diffuse than measured experimentally and the turbulence length scale of the simulated data is 1.5 times greater than that deduced from the measurements while the simulation based dissipation rate is slightly less than the measurement based value. The overprediction of the length scale is shown to potentially have a significant effect on the broadband noise. It is hypothesized that the overprediction is due to the usage of a trip to trigger the turbulent transition on the rotor blade in the computation. This preliminary study provides a path for more detailed wake evolution analysis using the simulation data as well as further flow comparisons for different stage configurations and fan operating speeds.
{"title":"Correction: Statistics and structure of turbulence in fan/FEGV interstage and their aeroacoustic implications","authors":"S. Grace, Ankush Gupta, Ignacio Gonzalez-Martino, D. Casalino","doi":"10.2514/6.2018-4186.C1","DOIUrl":"https://doi.org/10.2514/6.2018-4186.C1","url":null,"abstract":"Modern computational capabilities make simulations of complicated flow fields such as those in the fan stage of a turbofan engine possible. In particular, time resolved simulations are presenting new opportunities for studying the disturbances responsible for the broadband noise created by the fan stage. A preliminary quantitative analysis of the simulated flow field in the gap between the fan and fan exit guide vane (FEGV) computed with the Lattice Boltzmann based software PowerFLOW is presented. The study compares the simulated flow with experimental measurements to assess the mean flow, the turbulence intensity, the turbulence length scale and the turbulence dissipation rate. The mean wake is shown to be more diffuse than measured experimentally and the turbulence length scale of the simulated data is 1.5 times greater than that deduced from the measurements while the simulation based dissipation rate is slightly less than the measurement based value. The overprediction of the length scale is shown to potentially have a significant effect on the broadband noise. It is hypothesized that the overprediction is due to the usage of a trip to trigger the turbulent transition on the rotor blade in the computation. This preliminary study provides a path for more detailed wake evolution analysis using the simulation data as well as further flow comparisons for different stage configurations and fan operating speeds.","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122732415","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}
Aerofoils operating in a turbulent flow are an efficient source of noise radiation by scattering vorticity into sound at the leading edge. Much work has now been undertaken demonstrating the effectiveness by which serrations, or undulations, introduced onto the leading edge, can substantially reduce broadband leading edge interaction noise. However, all of this work is focused on sinusoidal leading edge serration profiles. In this paper, a family of alternative serration profiles are proposed that are capable of providing significantly greater noise reductions than single-wavelength serrations at optimal conditions. This new family of profiles will be shown to reduce interaction noise through a fundamentally different noise reduction mechanism than conventional single-wavelength profiles. Unlike single-wavelength profiles, which produce a single compact dominant source region per serration wavelength, these new profiles are designed to produce two dominant compact sources per serration wavelength of the same source strength, that are separated in the streamwise direction. Since these sources are arranged to be closer together than the turbulence length-scale, they are highly coherent and therefore radiate with a difference in phase. A frequency therefore exists at which the sources are exactly 180° out of phase leading to very high levels of noise reduction in the far field.
{"title":"Correction: On the superior performance of leading edge slits over serrations for the reduction of aerofoil interaction noise","authors":"Chaitanya C. Paruchuri, P. Joseph, Lorna J. Ayton","doi":"10.2514/6.2018-3121.C1","DOIUrl":"https://doi.org/10.2514/6.2018-3121.C1","url":null,"abstract":"Aerofoils operating in a turbulent flow are an efficient source of noise radiation by scattering vorticity into sound at the leading edge. Much work has now been undertaken demonstrating the effectiveness by which serrations, or undulations, introduced onto the leading edge, can substantially reduce broadband leading edge interaction noise. However, all of this work is focused on sinusoidal leading edge serration profiles. In this paper, a family of alternative serration profiles are proposed that are capable of providing significantly greater noise reductions than single-wavelength serrations at optimal conditions. This new family of profiles will be shown to reduce interaction noise through a fundamentally different noise reduction mechanism than conventional single-wavelength profiles. Unlike single-wavelength profiles, which produce a single compact dominant source region per serration wavelength, these new profiles are designed to produce two dominant compact sources per serration wavelength of the same source strength, that are separated in the streamwise direction. Since these sources are arranged to be closer together than the turbulence length-scale, they are highly coherent and therefore radiate with a difference in phase. A frequency therefore exists at which the sources are exactly 180° out of phase leading to very high levels of noise reduction in the far field.","PeriodicalId":429337,"journal":{"name":"2018 AIAA/CEAS Aeroacoustics Conference","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125937302","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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