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Peerlings, L., Boij, S. & Bodén, H. (2019). Experimental investigation of the aero-acoustic interaction at an area-expansion. Journal of Sound and Vibration, 457, 197-211
Open this publication in new window or tab >>Experimental investigation of the aero-acoustic interaction at an area-expansion
2019 (English)In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 457, p. 197-211Article in journal (Refereed) Published
Abstract [en]

Experimental results on the aero-acoustic interaction at an area expansion are scarce. In this study, new experimental data is acquired of the aero-acoustic interaction at an area expansion and compared with recent modeling efforts. The aero-acoustic interaction at an area expansion with expansion ratio eta = 0.309 is investigated by measuring the scattering matrix for plane waves at 5 different flow speeds in the incompressible regime. The experimental results are complimented with a comprehensive uncertainty analysis to determine the precision of the data. The scattering coefficients together with derived quantities such as absorption coefficients and dimensionless end corrections are compared against recent analytical results. It is shown that there is consistent deviation between the models and measurement results for certain scattering coefficients. The measured end correction on Strouhal number close to the critical Strouhal number shows a relatively abrupt change. This in comparison with the models, where the change is predicted to be more gradual. Similar observations are made for the absorption coefficient for waves incident upstream of the area expansion, although a qualitative comparison is difficult to make in this case because of the strong influence of the flow downstream of the area-expansion on the results.

Place, publisher, year, edition, pages
Academic Press, 2019
Keywords
Area expansion, Acoustic-flow interaction, Kutta condition, Scattering matrix
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-255351 (URN)10.1016/j.jsv.2019.04.003 (DOI)000474195900012 ()2-s2.0-85067206353 (Scopus ID)
Note

QC 20190730

Available from: 2019-07-30 Created: 2019-07-30 Last updated: 2019-07-30Bibliographically approved
Netto Spillere, A. M., Zhang, Z., Cordioli, J. A., Åbom, M. & Bodén, H. (2019). Optimum Impedance in the Presence of an Inviscid Sheared Flow. Paper presented at 24th AIAA/CEAS Aeroacoustics Conference / AIAA/CEAS Aeronautics Conference, JUN 25-29, 2018, Atlanta, GA. AIAA Journal, 57(3), 1044-1054
Open this publication in new window or tab >>Optimum Impedance in the Presence of an Inviscid Sheared Flow
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2019 (English)In: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 57, no 3, p. 1044-1054Article in journal (Refereed) Published
Abstract [en]

In recent years, much effort has been devoted to find the "optimum impedance" (i.e., the impedance that results in the maximum modal decay rate in flow duct acoustics for a given frequency, Mach number, and azimuthal mode order). Although such analysis can be carried out by means of numerical simulations, analytical expressions can also be derived to predict the optimum impedance. Previous works have been concerned with the optimum impedance of higher-order modes in rectangular ducts with uniform flow. In this work, the analysis is expanded to circular ducts for both uniform and sheared inviscid flows. Focus is given to typical operating conditions found in turbofan engine intakes and vehicle exhaust systems. It is shown that, in certain conditions, the optimum impedance is affected even by the presence of a small boundary-layer thickness. It is also noted that, for low Helmholtz numbers, the optimum impedance may have a negative resistance.

Place, publisher, year, edition, pages
AMER INST AERONAUTICS ASTRONAUTICS, 2019
National Category
Aerospace Engineering
Identifiers
urn:nbn:se:kth:diva-246241 (URN)10.2514/1.J057526 (DOI)000459609400014 ()
Conference
24th AIAA/CEAS Aeroacoustics Conference / AIAA/CEAS Aeronautics Conference, JUN 25-29, 2018, Atlanta, GA
Note

QC 20190403

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-04-03Bibliographically approved
Zhang, Z., Bodén, H. & Åbom, M. (2019). The Cremer impedance: An investigation of the low frequency behavior. Journal of Sound and Vibration, 459, Article ID 114844.
Open this publication in new window or tab >>The Cremer impedance: An investigation of the low frequency behavior
2019 (English)In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 459, article id 114844Article in journal (Refereed) Published
Abstract [en]

The Cremer impedance concept based on mode merging is one method that can substantially improve the axial damping in a waveguide. Previous works on the Cremer impedance including a uniform grazing flow have exhibited unexpected phenomenon such as negative resistance in the low frequency range. The current paper is a continuation of earlier works by the authors to extend the investigation of the Cremer impedance with a focus on the low frequency range. Two independent investigations from the perspective of boundary layer effects and mode merging patterns are conducted to better understand the low frequency behavior of the Cremer impedance.

Place, publisher, year, edition, pages
Academic Press, 2019
Keywords
Cremer impedance, Low frequency range, Negative resistance, Boundary condition, Mode merging
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-257424 (URN)10.1016/j.jsv.2019.07.010 (DOI)000481404000034 ()2-s2.0-85070731741 (Scopus ID)
Note

QC 20190902

Available from: 2019-09-02 Created: 2019-09-02 Last updated: 2019-09-05Bibliographically approved
Xianghai, Q., Lin, D., Xiaodong, J., Åbom, M. & Bodén, H. (2018). A combined design method for optimal acoustic treatment of annular aeroengine inlet based on cremer impedance. In: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. Paper presented at 25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018, Hiroshima, Japan, 8 July 2018 through 12 July 2018 (pp. 1248-1255). International Institute of Acoustics and Vibration, IIAV, 2
Open this publication in new window or tab >>A combined design method for optimal acoustic treatment of annular aeroengine inlet based on cremer impedance
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2018 (English)In: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling, International Institute of Acoustics and Vibration, IIAV , 2018, Vol. 2, p. 1248-1255Conference paper, Published paper (Refereed)
Abstract [en]

A combined design method of impedance of acoustic nacelle is developed based on the Cremer impedance. First, the Cremer method is further extended to provide the theoretical optimum impedance for infinite uniform annular ducts in the presence of a single azimuthal mode and plug flow. Then, with the Cremer impedance being the initial value, the searching optimization based on a finite element sound propagation model is conducted to determine the impedance for maximizing noise reduction under the conditions of nearly actual duct geometry and flow. A design case of impedance of a typical aeroengine inlet is used to evaluate the method. The TL contour against impedance indicates that the combined design can avoid the local solution and find successfully the globally optimum impedance, thereby leading to the maximum sound attenuation. Additionally, the Cremer impedance is quite close to the final optimum impedance in this case, thereby providing not only a good initial impedance but also a proper searching space for the search optimization. Therefore, the combined design method is of high efficiency and accuracy.

Place, publisher, year, edition, pages
International Institute of Acoustics and Vibration, IIAV, 2018
Keywords
Acoustic treatment, Cremer method, Optimization design, Optimum impedance
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-241872 (URN)2-s2.0-85058716055 (Scopus ID)9781510868458 (ISBN)
Conference
25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018, Hiroshima, Japan, 8 July 2018 through 12 July 2018
Note

QC 20190125

Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-01-25Bibliographically approved
Surendran, A., Heckl, M. A., Peerlings, L., Boij, S., Bodén, H. & Hirschberg, A. (2018). Aeroacoustic response of an array of tubes with and without bias-flow. Journal of Sound and Vibration, 434, 1-16
Open this publication in new window or tab >>Aeroacoustic response of an array of tubes with and without bias-flow
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2018 (English)In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 434, p. 1-16Article in journal (Refereed) Published
Abstract [en]

Heat exchangers, consisting of tube arrays in a cross-flow are a vital component of power generation systems. They are of interest from an acoustic point of view, because they can reflect, transmit and absorb an incident sound wave; in other words, they have the potential to act as a sound absorber and even as a passive control device to prevent a thermoacoustic instability in the power generation system. This paper presents a fundamental study of the aeroacoustic response of a tube array with and without bias-flow (also called cross-flow). The study has a theoretical and experimental side. On the theoretical side, a new model, based on the assumption of quasi-steady flow, was developed to predict the acoustic reflection and transmission coefficient of a tube array with bias-flow. Also, the model by Huang and Heckl (Huang and Heckl, 1993, Acustica 78, 191-200) for the case without bias-flow was evaluated. On the experimental side, flow-duct experiments using a multi-microphone technique were performed to validate the predictions from both models. The agreement was found to be very good for low frequencies. The measurements revealed the limit of validity of the quasi-steady model in terms of the Strouhal number. Although this limit is quite low, our quasi-steady model can serve as a valuable tool for designers of heat exchangers.

Place, publisher, year, edition, pages
Academic Press, 2018
Keywords
Aeroacoustics, Low-frequency response, Tube array, Heat exchanger, Low mach number bias-flow, Duct flow
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-235429 (URN)10.1016/j.jsv.2018.07.022 (DOI)000444001700001 ()2-s2.0-85050697044 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme
Note

QC 20180927

Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2018-09-27Bibliographically approved
Peerlings, L., Bake, F., Boij, S. & Bodén, H. (2018). Assessing the stochastic error of acoustic scattering matrices using linear methods. INTERNATIONAL JOURNAL OF SPRAY AND COMBUSTION DYNAMICS, 10(4), 380-392
Open this publication in new window or tab >>Assessing the stochastic error of acoustic scattering matrices using linear methods
2018 (English)In: INTERNATIONAL JOURNAL OF SPRAY AND COMBUSTION DYNAMICS, ISSN 1756-8277, Vol. 10, no 4, p. 380-392Article in journal (Refereed) Published
Abstract [en]

To be able to compare the measured scattering matrices with model predictions, the quality of the measurements has to be known. Uncertainty analyses are invaluable to assess and improve the quality of measurement results in terms of accuracy and precision. Linear analyses are widespread, computationally fast and give information of the contribution of each error source to the overall measurement uncertainty; however, they cannot be applied in every situation. The purpose of this study is to determine if linear methods can be used to assess the quality of acoustic scattering matrices. The uncertainty in measured scattering matrices is assessed using a linear uncertainty analysis and the results are compared against Monte-Carlo simulations. It is shown that for plane waves, a linear uncertainty analysis, applied to the wave decomposition method, gives correct results when three conditions are satisfied. For higher order mode measurements, the number of conditions that have to be satisfied increases rapidly and the linear analysis becomes an unsuitable choice to determine the uncertainty on the scattering matrix coefficients. As the linear uncertainty analysis is most suitable for the plane wave range, an alternative linear method to assess the quality of the measurements is investigated. This method, based on matrix perturbation theory, gives qualitative information in the form of partial condition numbers and the implementation is straightforward. Using the alternative method, the measurements of higher order modes are analyzed and the observed difference in the measured reflection coefficients for different excitation conditions is explained by the disparity in modal amplitudes.

Place, publisher, year, edition, pages
SAGE PUBLICATIONS INC, 2018
Keywords
Uncertainty analysis, higher order modes, sensitivity analysis, partial condition numbers, in-duct acoustics
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-241016 (URN)10.1177/1756827718789066 (DOI)000453453000010 ()2-s2.0-85058573682 (Scopus ID)
Note

QC 20190108

Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-08-20Bibliographically approved
Zhang, Z., Tiikoja, H., Åbom, M. & Bodén, H. (2018). Experimental analysis of whistle noise in a particle agglomeration pipe. In: INTER-NOISE 2018 - 47th International Congress and Exposition on Noise Control Engineering: Impact of Noise Control Engineering. Paper presented at 47th International Congress and Exposition on Noise Control Engineering: Impact of Noise Control Engineering, INTER-NOISE 2018, Marriott Magnificent Mile DowntownChicago, United States, 26 August 2018 through 29 August 2018. Institute of Noise Control Engineering
Open this publication in new window or tab >>Experimental analysis of whistle noise in a particle agglomeration pipe
2018 (English)In: INTER-NOISE 2018 - 47th International Congress and Exposition on Noise Control Engineering: Impact of Noise Control Engineering, Institute of Noise Control Engineering , 2018Conference paper, Published paper (Refereed)
Abstract [en]

A self-sustained sound, more usually known as a whistle, refers to a distinct tonal noise created due to the interaction between the sound and flow field. When a positive feedback loop is formed between the two fields, the energy in the mean flow will be transferred into the sound wave, thus giving rise to a whistle. In engineering practice, whistles are destructive as they can produce high sound and vibration levels and may result in risk for mechanical failures. In this work, a flow-related high level tonal noise was found during a measurement on a particle agglomeration pipe, which is a quasi-periodic corrugated structure designed for the exhaust system of heavy-duty trucks. The purpose of the pipe is to enhance particle agglomeration to increase the size of exhaust gas particles. To investigate the origin of the detected tonal noise additional measurements were carried out. Based on the measurement result, the aero-acoustic coupling in the agglomeration pipe was analyzed, revealing that the pipe has a large potentiality to amplify the incident sound power in the presence of a mean flow. Furthermore, the Nyquist stability criterion was applied to confirm the existence of exponentially growing modes in the system at certain conditions.

Place, publisher, year, edition, pages
Institute of Noise Control Engineering, 2018
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-241859 (URN)000456356800019 ()2-s2.0-85059372519 (Scopus ID)
Conference
47th International Congress and Exposition on Noise Control Engineering: Impact of Noise Control Engineering, INTER-NOISE 2018, Marriott Magnificent Mile DowntownChicago, United States, 26 August 2018 through 29 August 2018
Note

QC 20190122

Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-05-14Bibliographically approved
Bodén, H., Khodashenas, N. S. & Boij, S. (2018). Experimental study of nonlinear acoustic properties of perforates using band-limited random excitation information. In: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. Paper presented at 25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018, Hiroshima, Japan, 8 July 2018 through 12 July 2018 (pp. 1818-1825). International Institute of Acoustics and Vibration, IIAV, 3
Open this publication in new window or tab >>Experimental study of nonlinear acoustic properties of perforates using band-limited random excitation information
2018 (English)In: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling, International Institute of Acoustics and Vibration, IIAV , 2018, Vol. 3, p. 1818-1825Conference paper, Published paper (Refereed)
Abstract [en]

Perforates are used for noise control in automotive mufflers and aircraft engine liners as well as for other vehicles and machines. Their acoustic properties and noise reduction are known to depend on the mean flow field and other parameters such as temperature and acoustic excitation level. It is therefore of interest to understand how the properties of perforates varies with the level of acoustic excitation. This paper gives an overview of high level nonlinear effects on the acoustic properties of perforates. It includes semi-empirical models as well as experimental studies. Methods for studying nonlinear effects and harmonic interaction effects, for perforates, using single tone excitation and Poly-harmonic distortion models or nonlinear scattering matrices are discussed. These techniques typically require measurements with a number of different acoustic loads. It would be more attractive to directly be able to extract the nonlinear acoustic properties from a more limited set of experiments using either random or periodic excitation. Multi input - single output techniques for nonlinear system identification using broadband random excitation has been tried with limited success. One reason is the mixing of the sound pressure signal incident from the acoustic source with the sound pressure transferred to higher frequencies by nonlinear effects at the perforate sample. The present paper includes an attempt to combine band-limited broadband excitation with Poly-harmonic distortion models or nonlinear scattering matrices describing the nonlinear transfer of energy to higher frequencies.

Place, publisher, year, edition, pages
International Institute of Acoustics and Vibration, IIAV, 2018
Keywords
Acoustic properties, Aeroacoustics, Nonlinear system identification, Perforates
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-241887 (URN)2-s2.0-85058683457 (Scopus ID)9781510868458 (ISBN)
Conference
25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018, Hiroshima, Japan, 8 July 2018 through 12 July 2018
Note

QC 20190125

Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-01-25Bibliographically approved
Zhang, Z., Bodén, H., Åbom, M., Lin, D. & Xiaodong, J. (2018). Investigation of the 'exact' cremer impedance. In: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. Paper presented at 25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018; Hiroshima; Japan; 8 July 2018 through 12 July 2018 (pp. 1810-1817). International Institute of Acoustics and Vibration, IIAV
Open this publication in new window or tab >>Investigation of the 'exact' cremer impedance
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2018 (English)In: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling, International Institute of Acoustics and Vibration, IIAV , 2018, p. 1810-1817Conference paper, Published paper (Refereed)
Abstract [en]

The Cremer impedance, first proposed by Cremer (Acustica 3, 1953) and then improved by Tester (JSV 28, 1973), refers to the locally reacting boundary condition that can maximize the attenuation of a certain acoustic mode in a uniform waveguide. One limitation in Tester's work is that it simplified the analysis on the effect of flow by only considering high frequencies or the 'well cut-on' modes. This approximation is reasonable for large duct applications, e.g., aero-engines, but not for many other cases of interest such as the vehicle intake and exhaust systems. A recent modification done by Kabral et al. (Acta Acustica united with Acustica 102, 2016) has removed this limitation and investigated the 'exact' solution of Cremer impedance, which reveals an appreciable difference between the exact and classic solution in the low frequency range. A measurement campaign is here carried out to experimentally demonstrate such difference. In addition, the exact solution is found to exhibit some special properties at very low frequencies, e.g., a negative resistance. One can question if this negative resistance is physically correct or an artefact of the assumption of a plug flow profile and the use of the so-called Ingard-Myers boundary condition. To investigate this the Cremer solution is here extended to the case with a more general and realistic flow profile, using a modified version of the Ingard-Myers condition suggested by Brambley (AIAA J 49(6), 2011).

Place, publisher, year, edition, pages
International Institute of Acoustics and Vibration, IIAV, 2018
Keywords
'exact' solution, Boundary condition, Cremer impedance, Experimental analysis
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-246527 (URN)2-s2.0-85058677640 (Scopus ID)9781510868458 (ISBN)
Conference
25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018; Hiroshima; Japan; 8 July 2018 through 12 July 2018
Note

QC 20190403

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-04-03Bibliographically approved
Spillere, A. M., Zhang, Z., Cordioli, J. A., Åbom, M. & Bodén, H. (2018). Optimum impedance in the presence of an inviscid sheared flow. In: 2018 AIAA/CEAS Aeroacoustics Conference: . Paper presented at AIAA/CEAS Aeroacoustics Conference, 2018, Atlanta, United States, 25 June 2018 through 29 June 2018. American Institute of Aeronautics and Astronautics, Article ID AIAA 2018-3777.
Open this publication in new window or tab >>Optimum impedance in the presence of an inviscid sheared flow
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2018 (English)In: 2018 AIAA/CEAS Aeroacoustics Conference, American Institute of Aeronautics and Astronautics, 2018, article id AIAA 2018-3777Conference paper, Published paper (Refereed)
Abstract [en]

In recent years, much effort has been devoted to find the “optimum impedance” i.e. the impedance that results in the maximum modal decay rate in flow duct acoustics. Although such analysis can be carried out by means of numerical simulations, analytical expressions can also be derived in order to predict the optimum impedance. Previous works have been concerned over the optimum impedance of higher order modes in rectangular ducts with uniform flow. In this work, the analysis is expanded to circular and rectangular ducts for both uniform and sheared inviscid flows. Focus is given on a typical aero-engine intake and flight conditions. It is shown that, in certain conditions, the optimum impedance is affected even by the presence of a small boundary layer thickness. It is also noted that for low Helmholtz numbers the optimum impedance may have a negative resistance.

Place, publisher, year, edition, pages
American Institute of Aeronautics and Astronautics, 2018
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-233739 (URN)10.2514/6.2018-3777 (DOI)2-s2.0-85051301729 (Scopus ID)9781624105609 (ISBN)
Conference
AIAA/CEAS Aeroacoustics Conference, 2018, Atlanta, United States, 25 June 2018 through 29 June 2018
Note

QC 20180831

Available from: 2018-08-31 Created: 2018-08-31 Last updated: 2018-08-31Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-8474-8563

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