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Zhang, Zhe
Publications (9 of 9) Show all publications
Zhang, Z. (2019). Optimal damping and slow sound in ducts. (Doctoral dissertation). KTH Royal Institute of Technology
Open this publication in new window or tab >>Optimal damping and slow sound in ducts
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The thesis is dedicated to expanding knowledge on two duct acoustic issues including: 1) the optimal damping of low frequency sound and 2) the development and application of ‘slow sound’.

To address the first issue, the ‘Cremer impedance’ proposed more than half a century ago has been revisited and further developed. The original motivation is to extend the concept from large duct applications, such as aero-engines, to low frequency applications including vehicle intake and exhaust or cooling and ventilation systems. This leads to the derivation of the ‘exact’ solution of the Cremer impedance for single-lined rectangular ducts valid in the low frequency range in the presence of a ‘plug’ flow. A substantial improvement in the low frequency damping is achieved with the exact solution and a measurement campaign is carried out to validate this.

However, for both circular and rectangular ducts (including single-lined and double-lined types) the exact solution of the Cremer impedance has a negative real part in the low frequency range. This indicates that an active boundary is required to provide the optimal damping. Two investigations on the negative resistance are conducted. First, the ‘plug’ flow is replaced by a sheared flow by changing the boundary condition in the optimization model. With this modification, the Cremer impedance is recalculated and the negative resistance is still found in most cases, demonstrating that the negative resistance is not necessarily an artefact of the boundary condition. Second, since the Cremer impedance is based on mode-merging, a mode-merging analysis is carried out. The merging result shows that the downstream results are always valid, but some of the upstream results in the low frequency range are invalid in the sense that unexpected mode pairs merge, and the corresponding damping is smaller than expected. This finding is true for both the fundamental mode and higher order modes.

Regarding the second issue, ‘slow sound’ or sound with a much reduced ‘phase velocity’ is investigated using a resonant periodic system in the low frequency range. This can be seen as an acoustic metamaterial where sound propagates at a much smaller-than-normal speed around its resonance frequency. Following a hydrodynamic particle agglomeration model, the slow sound is applied to manipulate the distribution of small particles in the vehicle exhaust system. Although in principle this acoustic agglomeration method can work, it will only be efficient if the wave damping in the metamaterial is kept small. 

Abstract [sv]

Denna avhandling har till syfte att öka kunskapen om akustiska problem i kanaler, inklusive: 1) optimal dämpning av lågfrekvent ljud och; 2) utveckling och tillämpning av ‘slow sound’.När det gäller det första problemet, har ‘Cremer-impedansen’, som föreslogs för mer än ett halvt sekel sedan studerats och vidareutvecklats. Detta möjliggör nya tillämpningar svarande mot lågfrekvent ljud som insugnings- och avgassystem för fordon samt ventilationssystem. En ‘exakt’ lösning av Cremer-impedansen för rektangulära kanaler med en ljuddämpande vägg giltig i lågfrekvensområdet har härletts. En väsentlig förbättring av lågfrekvent dämpning har uppnåtts med denna lösning vilket även validerats med mätningar.Emellertid har den exakta lösningen av Cremer-impedansen en negativ realdel (‘resistans’) i lågfrekvensområdet, vilket betyder att en aktiv väggbeklädnad är nödvändig för att åstadkomma optimal dämpning. Två undersökningar av den negativa resistansen har genomförts för att studera om dessa lösningar är realiserbara. I den första ändrades randvillkoret för att inkludera gränsskikt i strömningen. Resultatet visade att negativ resistans erhålls i de flesta fall även med det modifierade randvillkoret. I den andra studerades lösningens giltighet i det komplexa vågtalsplanet. Resultatet visade att lösningen nedströms alltid är giltig medan vissa lösningar uppströms i lågfrekvensområdet är ogiltiga. Detta resultat gäller i princip för alla vågor eller moder i en kanal.När det gäller det andra problemet undersöktes möjligheterna att skapa ‘slow sound’, dvs ljud som utbreder sig mycket långsammare än normalt, genom att utnyttja ett resonant periodiskt system i en kanal i lågfrekvensområdet. Detta kan ses som ett s.k. akustiskt metamaterial och kan nyttjas för att med hjälp av starka ljudvågor påverka små partiklar som tvingas att kollidera och bli större. En studie om denna metod för sammanslagning av partiklar (‘particle agglomeration’) kan nyttjas för avgasrening har genomförts. Metoden är teoretiskt möjlig men begränsad av att tekniken för att skapa ‘slow sound’ inte bara saktar ned ljudvågen utan även dämpar dess amplitud och därigenom minska ljudvågens påverkan på partiklar.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2019. p. 75
Series
TRITA-SCI-FOU ; 2019:22
National Category
Fluid Mechanics and Acoustics
Research subject
Vehicle and Maritime Engineering
Identifiers
urn:nbn:se:kth:diva-251443 (URN)978-91-7873-176-3 (ISBN)
Public defence
2019-06-04, F3, Lindstedtsvägen 26, Stockholm, 10:15 (English)
Opponent
Supervisors
Note

QC20190514

Available from: 2019-05-14 Created: 2019-05-14 Last updated: 2019-05-14Bibliographically 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
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
Zhang, Z., Tiikoja, H., Peerlings, L. & Åbom, M. (2018). Experimental Analysis on the 'Exact' Cremer Impedance in Rectangular Ducts. 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 technical paper series, 2018-June(June)
Open this publication in new window or tab >>Experimental Analysis on the 'Exact' Cremer Impedance in Rectangular Ducts
2018 (English)In: SAE technical paper series, ISSN 0148-7191, Vol. 2018-June, no JuneArticle in journal (Refereed) Published
Abstract [en]

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, with the vehicle intake and exhaust system included. 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 for circular waveguides, which reveals an appreciable difference between the exact and classic solution in the low frequency range. Consequently, the exact solution can lead to a much higher low-frequency attenuation level. In addition, the exact solution is found to exhibit some special properties at very low frequencies, e.g., a negative resistance. In this paper, liners designed on the basis of the exact solution are tested and the difference between the exact and classic solution in the low frequency range (not low enough to go into the negative resistance region) is experimentally investigated.

Place, publisher, year, edition, pages
SAE International, 2018
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:kth:diva-238194 (URN)10.4271/2018-01-1523 (DOI)2-s2.0-85050564046 (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 20181120

Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2019-05-14Bibliographically 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
Kim, D.-Y. -., Ih, J.-G. -., Zhang, Z. & Åbom, M. (2017). A virtual herschel-quincke tube using slow sound. In: INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet. Paper presented at 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, INTER-NOISE 2017, 27 August 2017 through 30 August 2017. Institute of Noise Control Engineering
Open this publication in new window or tab >>A virtual herschel-quincke tube using slow sound
2017 (English)In: INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, Institute of Noise Control Engineering , 2017Conference paper, Published paper (Refereed)
Abstract [en]

While an acoustic wave propagates along a duct, of which the wall is treated with either dissipative or a reactive material, the phase speed can be slowed down because of wave dispersion. It has been thought that such slow sound can be used for a novel control method to reduce the in-duct noise at low to medium frequencies generated from a fluid machinery system. In this work, the Herschel-Quincke tube (hereafter, H-Q tube), which exploits the path length difference of two parallel ducts, is modified to demonstrate the application potential of the slow sound. A test rig is designed to create the two different phase speeds by arranging the two parallel, equal-length ducts inside a main duct, one of them is hard-walled and the other one lined with a periodic array of resonators. This slow sound H-Q device is then modelled by both analytical and numerical methods assuming a plane wave incidence. Also, an experiment is conducted to measure the transmission loss. The result reveals a low frequency peak (TL-30 dB) in the range of 200-400 Hz, which occurs far below the lowest resonance of the resonator. At the original resonance frequency of 691 Hz, a small attenuation (TL~6 dB) is obtained due to the fact that one duct is subject to a high loss, and the other is without appreciable loss. The result clearly demonstrates the potential of applying slow sound device to overcome the spatial limitation of the classical H-Q tube.

Place, publisher, year, edition, pages
Institute of Noise Control Engineering, 2017
Keywords
Acoustic metamaterial, Herschel-quincke tube, Parallel ducts, Slow sound, Transmission loss
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-224422 (URN)2-s2.0-85042121454 (Scopus ID)
Conference
46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, INTER-NOISE 2017, 27 August 2017 through 30 August 2017
Note

QC 20180319

Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2018-03-19Bibliographically approved
Zhang, Z., Åbom, M. & Bodén, H.‘Double-’ and ‘Triple-root’ Cremer Impedancefor a Rectangular Duct with Opposite Lined Walls.
Open this publication in new window or tab >>‘Double-’ and ‘Triple-root’ Cremer Impedancefor a Rectangular Duct with Opposite Lined Walls
(English)Manuscript (preprint) (Other academic)
Abstract [en]

To achieve high low frequency damping in an infinitely long double-lined rectangular duct with zero mean flow, the optimization of axial sound attenuation in the sense defined by Cremer (i.e., using the ‘Cremer impedance/solution’ concept) is examined for the fundamental mode. Two double-root Cremer impedance solutions that merge a mode pair into a single mode are presented. Different mode-merging patterns due to symmetry are found for these two solutions. As an extension, two triple-root Cremer impedance solutions (including one with a negative resistance) that merge three modes are also provided by extending the optimum condition proposed by Cremer. The two triple root solutions are theoretically advantageous in damping compared with the double root solutions, and the advantage is explained from the perspective of mode-merging.

National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-251440 (URN)
Note

QC 20190520

Available from: 2019-05-14 Created: 2019-05-14 Last updated: 2019-05-20Bibliographically approved
Zhang, Z., Bodén, H. & Åbom, M.The Cremer Impedance: An Investigation of the Low Frequency Behavior.
Open this publication in new window or tab >>The Cremer Impedance: An Investigation of the Low Frequency Behavior
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The Cremer impedance, first proposed by Cremer (1953) and then extended by Tester (1973), is supposed to give the maximum propagation damping in an infinitely long waveguide. Previous works including a uniform grazing flow have shown negative resistance in the low frequency range for both circular and 2-D rectangular waveguides, i.e., implying an active boundary. In order to further analyze the low frequency behaviour of the Cremer impedance, especially the negative resistance, two investigations are conducted in the current work. First, the previously used Ingard-Myers boundary condition is replaced by the Brambley boundary condition with the introduction of a thin inviscid boundary layer, and results obtained with the two boundary conditions are compared to see the effect of a sheared flow. The frequency range where the two boundary conditions can be applied is also analyzed. Second, discussions regarding the validity of the low frequency result in both the up- and downstream directions from the perspective of mode-merging are presented. This analysis is further extended from the fundamental mode to higher order modes in the frequency range where they are ‘just cut-on’.

Keywords
the Cremer impedance; low frequency range; negative resistance; boundary condition; mode-merging
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-251437 (URN)
Note

QC 20190520

Available from: 2019-05-14 Created: 2019-05-14 Last updated: 2019-05-20Bibliographically approved
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