International Journal of Aeroacoustics最新文献

A comparison of in situ and impedance eduction experimental techniques for acoustic liners with grazing flow and high sound pressure level 针对掠流和高声压级声学衬垫的原位和阻抗衰减实验技术比较

IF 1 4区工程技术

International Journal of Aeroacoustics Pub Date : 2024-01-05 DOI: 10.1177/1475472x231225629

L. A. Bonomo, Nicolas T. Quintino, André M N Spillere, Paul B Murray, J. Cordioli

{"title":"A comparison of in situ and impedance eduction experimental techniques for acoustic liners with grazing flow and high sound pressure level","authors":"L. A. Bonomo, Nicolas T. Quintino, André M N Spillere, Paul B Murray, J. Cordioli","doi":"10.1177/1475472x231225629","DOIUrl":"https://doi.org/10.1177/1475472x231225629","url":null,"abstract":"Several techniques are available to characterize acoustic liners when subject to grazing flow and high sound pressure level (SPL). Although the in situ technique started as the primary experimental procedure, impedance eduction techniques have gained popularity over the past years. However, there is a lack of comparison between these group of methods, especially at conditions typically found in turbofan engines. In this work, in situ and impedance eduction techniques are compared at high flow velocities and SPL using typical acoustic liner test samples and considering uniform flow. Both upstream and downstream acoustic wave propagation will also be considered in view of the discrepancies recently observed by eduction methods. A new method to compensate the instrumentation effect in the in situ technique is proposed and validated. Results are obtained for bulk Mach numbers up to 0.5 and SPLs up to 145 dB for both in situ and two eduction techniques. The three methods presents good agreement in the absence of flow. Unexpected results are observed with higher flow Mach numbers using the eduction technique.","PeriodicalId":49304,"journal":{"name":"International Journal of Aeroacoustics","volume":"88 21","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the balance between the tonal and broadband noise of isolated propellers 孤立螺旋桨的音调噪声和宽带噪声之间的平衡

IF 1 4区工程技术

International Journal of Aeroacoustics Pub Date : 2024-01-05 DOI: 10.1177/1475472x231225631

Deepak C. Akiwate, Phillip Joseph, Anthony B. Parry, Chaitanya Paruchuri

{"title":"On the balance between the tonal and broadband noise of isolated propellers","authors":"Deepak C. Akiwate, Phillip Joseph, Anthony B. Parry, Chaitanya Paruchuri","doi":"10.1177/1475472x231225631","DOIUrl":"https://doi.org/10.1177/1475472x231225631","url":null,"abstract":"This study presents a predominantly numerical and theoretical investigation into the balance of tonal and broadband noise due to an isolated propeller in uniform motion. The predicted trends in the balance between tonal and broadband noise radiation with varying blade number and speed of rotation is supported by preliminary experimental measurements. Here, we assume that the dominant noise generation mechanisms are the tones due to steady loading and blade thickness, while the broadband noise is due to boundary layer scattering at the trailing edge. The study also provides a detailed comparison between the tonal and broadband formulations to highlight their similarities and differences. In this paper, we show that the main differences in the behaviour and character of the tonal and broadband spectra and directivities are due to the number of acoustic modes that can be excited. This paper presents a parametric study in which the variation in tonal and broadband noise is investigated as a function of blade tip Mach number ( M t) and blade number ( B) whilst maintaining constant solidity and thrust. This study is repeated for three NACA airfoil profiles. It is found that tonal noise dominates at low blade number and low frequency and/or higher tip speeds, while broadband noise is the major contributor at high-frequencies and at high blade number and low tip speeds. The results show a clear distinction between the combinations of M t and B that are dominated by tonal and by broadband noise. These results are interpreted from fundamental principles relating to modal radiation efficiencies. We confirm this trend of balance between tonal and broadband noise with measured noise at different B and M t. The results of this paper will serve as useful guidelines for preliminary propeller design.","PeriodicalId":49304,"journal":{"name":"International Journal of Aeroacoustics","volume":"115 15","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139383387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Acoustic measurements in single-rotor/wing interaction at low disk loading and Reynolds number 低盘载荷和雷诺数条件下单旋翼/翼面相互作用的声学测量结果

IF 1 4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-12-30 DOI: 10.1177/1475472x231225630

Mingtai Chen, Jie Hua, Nick Maier, Dylan Burdette

{"title":"Acoustic measurements in single-rotor/wing interaction at low disk loading and Reynolds number","authors":"Mingtai Chen, Jie Hua, Nick Maier, Dylan Burdette","doi":"10.1177/1475472x231225630","DOIUrl":"https://doi.org/10.1177/1475472x231225630","url":null,"abstract":"The tiltrotor design is favored for urban air mobility (UAM) prototypes due to the combination of vertical takeoff and landing (VTOL) capability and efficient forward flight. With rising UAM air traffic at low altitudes, noise from these aircraft is a crucial design factor. Most tiltrotor noise research focuses on high disk loading and Reynolds number setups, leaving smaller aircraft configurations less explored. This study investigates aero-acoustic trends from rotor-wing interaction at low disk loading ([Formula: see text]100 N/m2) and Reynolds number (Re < 100,000). While prior literature suggests lowering disk loading and reducing rotor wake interference can mitigate rotor noise, such ideas lack empirical validation. The setup involves an anechoic chamber housing a two-blade rotor, along with flat and NACA 0012 airfoil wings. Microphones and a rotation stage capture acoustic data for analysis. Factors like flow recirculation, isolated rotor noise, rotor height, rotation direction/rate, and wing curvature are assessed for impact on noise signature. It is found that the deflected rotor wake in rotor-wing interaction significantly increases low-frequency broadband noise and overall sound pressure level (OASPL), compared to an isolated rotor. Dominant tonal noise diminishes based on the strength of the deflected rotor wake. These findings offer insights into reducing noise from rotor wake impingement on the wing.","PeriodicalId":49304,"journal":{"name":"International Journal of Aeroacoustics","volume":" 6","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139140941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Supersonic jet noise and screech tone suppression using cross-wire 利用交叉线抑制超音速喷气噪声和尖啸声

IF 1 4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-12-29 DOI: 10.1177/1475472x231225628

Kaleeswaran Periyasamy, Kadiresh Parthasarathy Natarajan

{"title":"Supersonic jet noise and screech tone suppression using cross-wire","authors":"Kaleeswaran Periyasamy, Kadiresh Parthasarathy Natarajan","doi":"10.1177/1475472x231225628","DOIUrl":"https://doi.org/10.1177/1475472x231225628","url":null,"abstract":"This experimental investigation is aimed at assessing how the introduction of a cross-wire at the exit of a CD nozzle influences the performance of a supersonic nozzle. The study focuses on cold air jets generated by De Laval nozzles equipped with cross-wires and baseline configurations, particularly at design Mach numbers of 1.5 and 1.75. The investigation involves collecting measurements from the noise field emitted by the cross-wire nozzle with a 2% obstruction at the exit. This passive control approach effectively reduces the occurrence of screech tones in both over-expanded and under-expanded conditions in the azimuthal plane at appropriate operating pressures. Various acoustic parameters, including sound pressure levels (SPL), Strouhal numbers, and the overall sound pressure level spectra (OASPL) are recorded. Schlieren imaging captures images of shock cell patterns, illustrating the impact of shock-associated noise. In comparison to a baseline nozzle, the results demonstrate that a CD nozzle equipped with a cross-wire proves to be a proficient screech tone suppressor, leading to an average reduction of up to 5 dB in OASPL in under-expanded and over-expanded scenarios.","PeriodicalId":49304,"journal":{"name":"International Journal of Aeroacoustics","volume":"83 7","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139147260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Guest editor biography 特邀编辑简历

IF 1 4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-11-01 DOI: 10.1177/1475472X231219326

引用次数: 0

Guest editor biography 特邀编辑简历

IF 1 4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-11-01 DOI: 10.1177/1475472x231219327

引用次数: 0

Trailing edge serrations for noise control in axial-flow automotive cooling fans 轴流汽车冷却风扇噪声控制的后缘锯齿

4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-10-14 DOI: 10.1177/1475472x231206498

Kwang Ho Hur, Basharat Ali Haider, Chang Hyun Sohn

{"title":"Trailing edge serrations for noise control in axial-flow automotive cooling fans","authors":"Kwang Ho Hur, Basharat Ali Haider, Chang Hyun Sohn","doi":"10.1177/1475472x231206498","DOIUrl":"https://doi.org/10.1177/1475472x231206498","url":null,"abstract":"This study investigated the use of trailing edge serrations to reduce the noise generated by axial-flow automotive cooling fans. Three different serration profiles (sinusoidal, rectangular, and triangular) were examined, with the profiles being extended radially along the entire blade length and truncated at half the blade length while keeping the dimensionless wave number k ∗ and wave amplitude 2 h ∗ constant. The simulations employed a hybrid URANS-LES solver for the flow field and Ffowcs Williams-Hawkings analogy for the sound field, corresponding to the maximum volumetric flow rate and fan rotational speed. Acoustic pressure measurements were taken at multiple receivers upstream and downstream of the fan, and the overall sound pressure level was computed based on the results. Furthermore, the study also compared the aerodynamic performance of all serration types with the baseline fan, revealing that the baseline fan was relatively more efficient than their serrated counterparts. Despite the reduced efficiency, the trailing edge serrations offered significant noise reduction benefits of up to 10 dB, making them a promising solution for improving acoustic comfort in automotive cooling systems.","PeriodicalId":49304,"journal":{"name":"International Journal of Aeroacoustics","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135800519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Acoustic characteristics of jets impinging on permeable plates 射流冲击透水板的声学特性

4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-10-10 DOI: 10.1177/1475472x231206496

Abhijit Dhamanekar, K Srinivasan

{"title":"Acoustic characteristics of jets impinging on permeable plates","authors":"Abhijit Dhamanekar, K Srinivasan","doi":"10.1177/1475472x231206496","DOIUrl":"https://doi.org/10.1177/1475472x231206496","url":null,"abstract":"This article explores the acoustic characteristics and the relevant flow features of jets impinging on permeable plates. Noise generated due to the interaction of the jet with permeable plates is compared with jets impinging on an impermeable plate and the corresponding free jet. This study systematically measures various parameters, including pore size, porosity, and pressure drop, to precisely quantify the permeability of the plates using the Forchheimer equation. The focus is on investigating the impact of permeability on noise reduction. An acoustic study is performed by carrying out blow-up and blow-down tests to find the effect of permeability at different nozzle pressure ratios and different nozzle-plate spacings. An extensive directivity study is conducted to find the directionality of acoustic emissions and calculate acoustic power. It is found that the overall sound pressure level is lower for the jets impinging on the permeable plates compared to the impermeable plates in subsonic cases. It is also observed that the insertion of the permeable plates in supersonic jets generates less noise compared to the corresponding free jet. It is found that most of the tones are absent in the case of permeable plates for supersonic jets, whereas the tones are present with lesser amplitude compared to jets impinging on impermeable plates for subsonic and transonic jets. Finally, flow measurement and flow visualization studies are carried out to understand the flow physics responsible for the noise variance. This study illuminates that the passage of flow through the porous plate results in the reduction of wall-jet velocities, thereby suppressing the turbulent mixing noise. The absence of shock oscillations in front of the permeable plate is identified as the cause of the mitigation of impinging tones.","PeriodicalId":49304,"journal":{"name":"International Journal of Aeroacoustics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136358363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of nozzle external geometry on the emission of screech tones 喷嘴外部几何形状对尖叫音调发射的影响

4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-10-05 DOI: 10.1177/1475472x231199185

David Morata, Dimitri Papamoschou

{"title":"Influence of nozzle external geometry on the emission of screech tones","authors":"David Morata, Dimitri Papamoschou","doi":"10.1177/1475472x231199185","DOIUrl":"https://doi.org/10.1177/1475472x231199185","url":null,"abstract":"The effect of external nozzle geometry on the emission of screech tones was studied experimentally. Four conical reflector surfaces, with half-angles ranging from 60° to 90°, were installed around the exit of a round convergent nozzle. The investigation focused on two closely spaced fully-expanded Mach numbers, M j = 1.32 and 1.34. The acoustic far-field was surveyed by a microphone phased array that included a continuously-scanning microphone, the latter enabling high spatial resolution. The isolated jets contained well-known screech mode B and its harmonics. Addition of the reflectors caused significant changes in the modal emission pattern, with tones traditionally linked to mode C occurring at M j = 1.34 but not at M j = 1.32. Tonal components associated with new modes E and F emerge at both Mach numbers when the cone half-angle is 60° or 70°. The noise source distribution generally elongates with decreasing cone angle. Some modes show clear scattering from the reflectors, while others do not. The study underscores the complexity that initial conditions can impart on the modal structure of screech and demonstrates the capability of the continuous-scan beamforming technique in resolving fine features of the source.","PeriodicalId":49304,"journal":{"name":"International Journal of Aeroacoustics","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135480822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Machine learning methods for multi-rotor UAV structural damage detection based on MEMS sensor 基于MEMS传感器的多旋翼无人机结构损伤检测机器学习方法

4区工程技术

International Journal of Aeroacoustics Pub Date : 2023-10-05 DOI: 10.1177/1475472x231206495

Yumeng Ma, Faizal Mustapha, Mohamad Ridzwan Ishak, Sharafiz Abdul Rahim, Mazli Mustapha

引用次数: 0