Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 176) Show all publications
Kim, D.-Y., Ih, J.-G. & Åbom, M. (2020). Virtual Herschel-Quincke tube using the multiple small resonators and acoustic metamaterials. Journal of Sound and Vibration, 466, Article ID UNSP 115045.
Open this publication in new window or tab >>Virtual Herschel-Quincke tube using the multiple small resonators and acoustic metamaterials
2020 (English)In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 466, article id UNSP 115045Article in journal (Refereed) Published
Abstract [en]

This study is on the practical application of the acoustic metamaterials to the design of a silencer with high acoustic and geometric efficiencies, and negligible pressure drop. The object is to achieve broadband and low-frequency attenuation simultaneously by combining the effects of resonance, periodicity, phase difference, and impedance mismatch. An array of multiple small resonators, which is periodically applied to the wall of a duct, invokes the dispersion of sound propagating in the duct. This phenomenon is implemented to construct a virtual Herschel-Quincke (HQ) tube system. The main duct is split into two parallel ducts of the same length: a rigid duct and a duct with a wall covered by the periodic resonators. For a modelling of sound propagation in a dispersive duct, the phase speed of sound is analytically derived in the presence of a mean flow. Also, the attenuation conditions of the virtual HQ tube are proposed to establish a guideline in selecting the proper design parameters for achieving the required transmission loss (TL) in the desired frequency range. The predicted TL spectra are compared with the test results, for a virtual HQ tube system with 9 identical quarter-wavelength tube resonators, and they generally agree well. With increasing flow speed, the amount of attenuation decreases a bit, but the general spectral characteristics are maintained for vertical bar M vertical bar <= 0.1. Based on the same principle, the acoustic metamaterials (AMM) are applied to the practical silencer design to achieve the wide-band sound reduction at low- to mid-frequencies for a given small space. A virtual HQ tube having 26 cells of AMM is tested, of which a cell is composed of 3 types of quarter-wavelength tube resonators. The experiment well validates the predicted TL. The results show that TL is at least 5 dB for a wide frequency range of 230-1000 Hz. The additional volume due to the attachment of the AMM layer is only 40%, while the TL is far larger than that of the simple expansion chamber or the dissipative silencer having the same excess volume.

Place, publisher, year, edition, pages
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2020
Keywords
Herschel-Quincke tube, Periodic resonators, Acoustic metamaterials, Transmission loss, Silencer
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-265848 (URN)10.1016/j.jsv.2019.115045 (DOI)000500341100004 ()2-s2.0-85074370180 (Scopus ID)
Note

QC 20200103

Available from: 2020-01-03 Created: 2020-01-03 Last updated: 2020-01-13Bibliographically approved
Tengzelius, U. & Åbom, M. (2019). Aircraft pass-by noise on ground modelled with the SAFT-program. In: Proceedings of the INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering: . Paper presented at INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering.
Open this publication in new window or tab >>Aircraft pass-by noise on ground modelled with the SAFT-program
2019 (English)In: Proceedings of the INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering, 2019Conference paper, Published paper (Refereed)
Abstract [en]

SAFT (Simulation of atmosphere and Air traffic For a quieter environmenT) is the name of a simulation tool for aircraft noise propagation that has been developed at CIT, Chalmers and KTH since the end of 2016. It is funded through CSA – Centre for Sustainable Aviation at KTH. Already in its current state SAFT enables aircraft pass-by noise estimations of several kinds. The set of computational approaches stretches from the most complex “full-simulation” ones, involving directivity, timeand frequency dependent individual (jet, fan, flaps, ...) noise sources as well as sound propagation through a refractive atmosphere, down to the more old-fashioned “integrated” computational methods such as given in ECAC doc.29. Special attention has been paid to making the tool user-friendly and fast to run. Even in the case with a refractive atmosphere model SAFT runs at rather short CPU-times thanks to a new concept of a Transmission Loss interpolation matrix. The typical result from SAFT-runs is either a noise-contour map (LAmax, SEL(A) or other metric) or the noise level time history in selected ground points (for simulation computations only). Other features involves possibilities to plot dB-contours from “any possible” model-, parameter- or aircraft procedure variation. E.g. comparison of results such as from ECAC doc.29 vs “full-simulation”, aircraft A vs aircraft B, weather condition X vs weather Y, different absorption models, different engine, airframe or procedure modifications etc. In a planned effort noise-source data in SAFT is to be extended with measured aircraft pass-by noise, time-correlated with FDR or/and trajectory data from the Opensky database. 

Keywords
: sound propagation, aircraft noise simulation
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-268268 (URN)2-s2.0-85077678261 (Scopus ID)
Conference
INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering
Note

QC 20200324

Available from: 2020-03-24 Created: 2020-03-24 Last updated: 2020-03-24
Baro, S., Corradi, R., Åbom, M., Caracino, P. & Fioravanti, A. P. (2019). Modelling of a lined tyre for predicting cavity noise mitigation. Applied Acoustics, 155, 391-400
Open this publication in new window or tab >>Modelling of a lined tyre for predicting cavity noise mitigation
Show others...
2019 (English)In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 155, p. 391-400Article in journal (Refereed) Published
Abstract [en]

Tyre cavity resonance can significantly affect vehicle interior noise at frequencies around 200 Hz. The insertion of a sound absorbing liner inside the tyre is known to be an efficient countermeasure, in fact nowadays tyre manufacturers are already producing tyres implementing this kind of solution. The present work, through analytical and numerical models, supported by material testing, provides a methodology for predicting the dag performance of a lined tyre, taking into account tyre/lining geometry and sound absorbing material properties. The results reported in the paper show that for fixed material characteristics, the attenuation of the cavity resonance is mostly influenced by the volume of the lining treatment. Moreover, the numerical model developed for discontinuous treatments, suggests that for fixed volume and material properties, the cavity resonance attenuation can be increased by choosing a proper layout. Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Cavity resonance, Tyre, Sound absorbing material, Predictive modelling
National Category
Fluid Mechanics and Acoustics
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-260981 (URN)10.1016/j.apacoust.2019.05.033 (DOI)000485209600037 ()2-s2.0-85067593295 (Scopus ID)
Note

QC 20191009

Available from: 2019-10-09 Created: 2019-10-09 Last updated: 2019-12-03Bibliographically 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
Show others...
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 ()2-s2.0-85066895083 (Scopus ID)
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: 2020-03-09Bibliographically approved
Zhou, J., Karlsson, M. & Åbom, M. (2019). Study of thermoacoustic engine for automotive exhaust waste heat recovery. Paper presented at 9 April 2019 through 11 April 2019. SAE technical paper series, 2019-April(April)
Open this publication in new window or tab >>Study of thermoacoustic engine for automotive exhaust waste heat recovery
2019 (English)In: SAE technical paper series, ISSN 0148-7191, Vol. 2019-April, no AprilArticle in journal (Refereed) Published
Abstract [en]

In this paper, the travelling-wave thermoacoustic engine (TAE) and its application for recovery of waste heat from automotive exhaust systems is investigated. The aim is to give some insight into the potential, but also limitations of the technique for practical applications. This includes packaging, physical boundary conditions as heating and cooling available, but also system perspectives as influence of legislative drive cycles and degree of hybridization. First, the travelling-wave TAE is described as a low-order acoustic network in the frequency domain. Models, including non-linear effects, are set up for every component in the network to describe the propagation and dissipation of acoustic waves. For a TAE with looped structure, the continuity of pressure and volumetric velocity is employed to determine the saturation pressure, as well as the stable operating point. These models are validated against experimental data available in the literature [1]. This is an engine designed for high-temperature application, but is well documented and yields a good reference for the models and to further the understanding of the TAE. Next, an optimized design for a system to be adapted to the operating conditions typical for heavy-duty systems is studied and proposed. No actual physical prototype has been built and verified, but the design is based on, and is of the same efficiency, as machines that have been reported in the literature. The proposed design and the original TAE are then used to discuss the practical implementation for heavy- and light-duty vehicles on a system level. To improve the utilization of the available exhaust waste heat, a configuration of system heat exchangers combining a self-circulating loop with multiple TAE modules is preliminarily studied. Further research for this configuration is needed for practical implementation although current simulation results are encouraging.

Place, publisher, year, edition, pages
SAE International, 2019
Keywords
Acoustic wave propagation, Computer system recovery, Digital storage, Frequency domain analysis, High temperature applications, Thermoacoustic engines, Thermoacoustics, Waste heat, Waste heat utilization, Wave transmission, Automotive exhaust, Automotive exhaust system, Current simulation, Degree of hybridization, Heating and cooling, Light duty vehicles, Operating condition, Saturation pressure, Exhaust systems (engine)
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-255938 (URN)10.4271/2019-01-1257 (DOI)2-s2.0-85064680284 (Scopus ID)
Conference
9 April 2019 through 11 April 2019
Note

QC 20190816

Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2019-08-16Bibliographically 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
Garnell, E., Åbom, M. & Banwell, G. (2019). The use of the two-port method to characterize high-speed small fans. Applied Acoustics, 146, 155-163
Open this publication in new window or tab >>The use of the two-port method to characterize high-speed small fans
2019 (English)In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 146, p. 155-163Article in journal (Refereed) Published
Abstract [en]

One way to obtain a complete characterization of a sound source in a duct is to measure two-port data, comprising of the source scattering matrix and the source cross-spectrum. The present paper discusses in detail the design and construction of a two-port rig to characterize high speed small fans. A new post-processing method is suggested for the source cross-spectrum data and is compared to an earlier published method. The new method is shown to behave better in highly reflective cases, but is more sensitive to flow noise. In some cases, the duct diameter is not equal to the diameter of the test object. An adaptor can then be used to match the diameters, but it will modify the two-port results. In the present paper a method to remove the adaptor influence on the measured scattering matrix and source vector is presented, and validated by measurements.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Two-port measurements, Test rig, Small fans
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-244497 (URN)10.1016/j.apacoust.2018.11.005 (DOI)000457662400017 ()2-s2.0-85057038584 (Scopus ID)
Note

QC 20190328

Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2019-04-04Bibliographically 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
Show others...
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
Rynell, A., Chevalier, M., Åbom, M. & Efraimsson, G. (2018). A numerical study of noise characteristics originating from a shrouded subsonic automotive fan. Applied Acoustics, 140, 110-121
Open this publication in new window or tab >>A numerical study of noise characteristics originating from a shrouded subsonic automotive fan
2018 (English)In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 140, p. 110-121Article in journal (Refereed) Published
Abstract [en]

The characteristics of the noise radiated from a reduced automotive cooling module are numerically studied focusing on the interaction effects linked to the sound generation mechanisms and the acoustic scattering caused by the confined installation. The flow field is simulated by adopting the formulation of Improved Delayed Detached Eddy Simulation (IDDES), which is a numerical technique that enables large-scale structures to be resolved and the wall-bounded flow to be treated depending on the turbulent content within the boundary layer. By comparing the simulated fan performance to two sets of measurement data of a similar setup, the aerodynamic results obtained from IDDES are validated and conformed to the volumetric flow rate delivered for the pressure drop measured. The acoustic part of the study comprises evaluation of the sound source associated with the momentum distribution imposed on the surroundings at an interface slightly upstream of the fan. At the microphone positions upstream of the installation, the SPL falls within the SPL range measured and the acoustic power delivered by the fan conforms to the SWL obtained from the comparison method in the reverberation room. The system response function, estimated by subtracting the SWL for the free-field simulation from the SWL associated with the reduced automotive cooling module marks spectral humps at fixed frequencies, irrespectively of sound source. As such, the engineering approach to the spectral decomposition method earlier published, which enables the acoustical properties of the installation to be isolated from the source, is validated and found to hold.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Aeroacoustics, Fan noise, IDDES, Installation effects, Spectral decomposition
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-228690 (URN)10.1016/j.apacoust.2018.05.006 (DOI)000440121900012 ()2-s2.0-85047243465 (Scopus ID)
Note

QC 20180529

Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2018-08-20Bibliographically approved
Pietroniro, A. G., Mihaescu, M., Åbom, M. & Knutsson, M. (2018). A Steady-State Based Investigation of Automotive Turbocharger Compressor Noise. In: SAE Technical Papers: . Paper presented at SAE 10th International Styrian Noise, Vibration and Harshness Congress: The European Automotive Noise Conference, SNVH 2018; Congress GrazSparkassenplatz 1Graz; Austria; 20 June 2018 through 22 June 2018. SAE International, 2018-June(June)
Open this publication in new window or tab >>A Steady-State Based Investigation of Automotive Turbocharger Compressor Noise
2018 (English)In: SAE Technical Papers, SAE International , 2018, Vol. 2018-June, no JuneConference paper, Published paper (Refereed)
Abstract [en]

The challenging problem of noise generation and propagation in automotive turbocharging systems is of real interest from both scientific and practical points of view. Robust and fast steady-state fluid flow calculations, complemented by acoustic analogies can represent valuable tools to be used for a quick assessment of the problem during e.g. design phase, and a starting point for more in-depth future unsteady calculations. Thus, as a part of the initial phase of a long-term project, a steady-state Reynolds Averaged Navier-Stokes (RANS) flow analysis is carried out for a specific automotive turbocharger compressor geometry. Acoustic data are extracted by means of aeroacoustics models available within the framework of the STAR-CCM+ solver (i.e. Curle and Proudman acoustic analogies, respectively). This part of the work focuses on the discussion and comparison of the aeroacoustic models, and their suitability towards predicting flow and acoustics trends corresponding to the operating conditions investigated. However, given the unsteady nature of acoustics, the project will have to develop towards an investigation of the problem using more expensive, but more accurate, Large Eddy Simulation (LES) calculations. An entire compressor map with 80 operating conditions was simulated, yielding trends in the behaviour of the performance parameters for the analysed compressor. Detailed results calculated on the same compressor speed-line for one design and one off-design operating conditions are presented in terms of time-averaged pressure coefficient, Mach number, and acoustic power distributions. A total acoustic power map has been generated based on the outcome from the Curle and Proudman acoustic models, giving an indication of the noisiest operating conditions.

Place, publisher, year, edition, pages
SAE International, 2018
National Category
Fluid Mechanics and Acoustics
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-238199 (URN)10.4271/2018-01-1528 (DOI)2-s2.0-85050556716 (Scopus ID)
Conference
SAE 10th International Styrian Noise, Vibration and Harshness Congress: The European Automotive Noise Conference, SNVH 2018; Congress GrazSparkassenplatz 1Graz; Austria; 20 June 2018 through 22 June 2018
Note

QC 20181116

Available from: 2018-11-16 Created: 2018-11-16 Last updated: 2019-06-27Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7898-8643

Search in DiVA

Show all publications