Acta Acustica united with Acustica最新文献_第7页

A Comparison of a One-Dimensional Finite Element Method and the Transfer Matrix Method for the Computation of Wind Music Instrument Impedance 一维有限元法与传递矩阵法在管乐器阻抗计算中的比较

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/AAA.919364

R. Tournemenne, J. Chabassier

{"title":"A Comparison of a One-Dimensional Finite Element Method and the Transfer Matrix Method for the Computation of Wind Music Instrument Impedance","authors":"R. Tournemenne, J. Chabassier","doi":"10.3813/AAA.919364","DOIUrl":"https://doi.org/10.3813/AAA.919364","url":null,"abstract":"This work presents a computation tool for the calculation of wind instrument input impedance in the context of linear planar wave propagation with visco-thermal losses. The originality of the approach lies in the usage of a specific and simple 1D finite element method (FEM). The popular\u0000 Transfer Matrix Method (TMM) is also recalled and a seamless formulation is proposed which unifies the cases cylinders vs. cones. Visco-thermal losses, which are natural dissipation in the system, are not exactly taken into account by this method when arbitrary shapes are considered. The introduction\u0000 of an equivalent radius leads to an approximation that we quantify using the FEM method. The equation actually solved by the TMM in this case is exhibited. The accuracy of the two methods (FEM and TMM) and the associated computation times are assessed and compared. Although the TMM is more\u0000 efficient in lossless cases and for lossy cylinders, the FEM is shown to be more efficient when targeting a specific precision in the realistic case of a lossy trumpet. Some additional features also exhibit the robustness and flexibility of the FEM over the TMM. All the results of this article\u0000 are computed using the open-source python toolbox OpenWind.","PeriodicalId":35085,"journal":{"name":"Acta Acustica united with Acustica","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90925503","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}

引用次数: 8

A Directional Converter of Longitudinal Vibration with One Input and Multiple Outputs 一种单输入多输出的纵向振动定向变换器

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/aaa.919355

He Xiping, Zhang Haidao

{"title":"A Directional Converter of Longitudinal Vibration with One Input and Multiple Outputs","authors":"He Xiping, Zhang Haidao","doi":"10.3813/aaa.919355","DOIUrl":"https://doi.org/10.3813/aaa.919355","url":null,"abstract":"Traditional power ultrasonic vibration systems can process one object at one time and only have one output. A directional converter of longitudinal vibration with multiple outputs composed of an input rod, a hemispherical vibrator, and three output rods is presented. The frequency equation\u0000 used in the design is derived with free edges at the input and output ends of the converter, as well as the continuity of displacements, forces, and angles of rotation at each component junction. The resonant frequencies of three fabricated converters designed using the proposed method are\u0000 in good agreement with those from the finite element method and also with tested values. With the input end of the converter joined with a piezoelectric transducer with a resonant frequency of 19.8 kHz, the longitudinal vibration modes and displacement amplitudes of the output ends of the\u0000 three converters at their resonant frequencies are tested. The results show that longitudinal vibration can be transferred from the input end to the multi-output ends through the converter. Furthermore, there exists a linear relationship between the excitation voltage and the displacements\u0000 of each output of the converter.","PeriodicalId":35085,"journal":{"name":"Acta Acustica united with Acustica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91212587","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}

引用次数: 0

Airfoil Trailing Edge Noise Reduction Using a Boundary-Layer Bump 利用边界层碰撞降低翼型后缘噪声

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/aaa.919362

Yuejun Shi, Seongkyu Lee

{"title":"Airfoil Trailing Edge Noise Reduction Using a Boundary-Layer Bump","authors":"Yuejun Shi, Seongkyu Lee","doi":"10.3813/aaa.919362","DOIUrl":"https://doi.org/10.3813/aaa.919362","url":null,"abstract":"This paper presents a new idea of reducing airfoil trailing edge noise using a small bump in the turbulent boundary layer. First, we develop and validate a new computational approach to predict airfoil trailing edge noise using steady RANS CFD, an empirical wall pressure spectrum model,\u0000 and Howe's diff raction theory. This numerical approach enables fast and accurate predictions of trailing edge noise, which is used to study the noise reduction from the bump for various airfoil geometries and flow conditions at high Reynolds numbers. Three types of bumps, the suction-side\u0000 bump, pressure-side bump, and both-side bumps, are studied. The results show that all types of bumps are able to reduce far-field noise up to 10 dB compared to clean airfoils, but their impacts are diff erent in terms of the eff ective frequency range. Also, bumps with four diff erent heights\u0000 are compared with each other to investigate the eff ect of the height of bumps on noise reduction. It is demonstrated that a bump causes velocity deficit within the boundary layer near the wall. This velocity deficit results in reduced turbulence kinetic energy near the wall, which is responsible\u0000 for trailing edge noise reduction. Overall, this paper demonstrates the potential of a boundary-layer bump in trailing edge noise reduction and sheds light on the physical mechanism of noise reduction with boundary-layer bumps.","PeriodicalId":35085,"journal":{"name":"Acta Acustica united with Acustica","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83496172","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}

引用次数: 11

Reconsideration on Helmholtz-Kirchhoff Integral Solutions for Boundary Points in Radiation Problems 辐射问题边界点Helmholtz-Kirchhoff积分解的再思考

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/aaa.919363

K. Been, W. Moon

{"title":"Reconsideration on Helmholtz-Kirchhoff Integral Solutions for Boundary Points in Radiation Problems","authors":"K. Been, W. Moon","doi":"10.3813/aaa.919363","DOIUrl":"https://doi.org/10.3813/aaa.919363","url":null,"abstract":"The Helmholtz-Kirchhoff integral (HKI) formula is very useful when designing transducers because it can be used to predict the acoustic pressure of a radiator at any position given only the acoustic pressure and velocity of the source. Many studies have been carried out to determine\u0000 how to predict the acoustic pressure distributions generated by radiator sources using the HKI formula and boundary conditions. However, if the surface integration process includes radiator edges or vertices, then it is difficult to predict a consistent acoustic pressure distribution accurately,\u0000 and the precise HKI formula to solve this problem and rigorous derivation are not known. In this article, to overcome these limitations, a formulation of the HKI for the boundary is proposed. This formulation is based on intuitive considerations and proven mathematically. Using the proposed\u0000 expression of the HKI formula for the boundary, the acoustic pressures radiated by irregular surfaces were calculated and compared with the distributions obtained by the finite element method and theoretically exact solutions. The results obtained with the proposed formulation of the HKI were\u0000 confirmed to be more accurate than those of the conventional HKI formula.","PeriodicalId":35085,"journal":{"name":"Acta Acustica united with Acustica","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76924617","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}

引用次数: 0

Ultrasonic Study of Molecular Interactions in Polymeric Solution of Polypropylene Glycol-400 and Ethanol at 303 K 聚丙烯-乙醇-400聚合物溶液中分子相互作用的超声研究

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/aaa.919354

Monika Dhiman, Kuljeet Singh, J. Kaushal, A. Upmanyu, D. Singh

{"title":"Ultrasonic Study of Molecular Interactions in Polymeric Solution of Polypropylene Glycol-400 and Ethanol at 303 K","authors":"Monika Dhiman, Kuljeet Singh, J. Kaushal, A. Upmanyu, D. Singh","doi":"10.3813/aaa.919354","DOIUrl":"https://doi.org/10.3813/aaa.919354","url":null,"abstract":"A comprehensive ultrasonic investigation of molecular interactions in the polymeric solution of polypropylene glycol (PPG)-400 and ethanol at 303 K has been performed using the data available in literature. Several acoustic parameters such as acoustic impedance, isothermal compressibility,\u0000 molar sound velocity, molar adiabatic compressibility, internal pressure, free volume, van der Waals constants, molar cohesive energy and relaxation time have been explored. Thermo-dynamical parameters viz.: available volume, intermolecular free length, relative association, surface tension,\u0000 pseudo-Gruneisen parameter, Debye temperature, diff usion constant, coefficient of thermal conductivity and latent heat of melting have been evaluated. Several thermo- elastic parameters such as Young modulus, shear modulus, bulk modulus and Poisson's ratio are also determined. Excess parameters\u0000 are computed to study the relative molecular interactions and strength of interaction between the constituents of the polymer mixture. The volume expansivity data is used to evaluate Moelwyn-Hughes parameter, reduced volume, reduced isothermal bulk modulus, Sharma's constants, Huggins parameter,\u0000 isobaric, isochoric, and isothermal lattice Gruneisen parameters, fractional free volume, repulsive exponent, Bayer's non-linear parameter, cohesive energy density and characteristic temperature. Schaaff 's collision factor theory, Jacobson's free length theory, Nomoto's relation, Van Dael-Vangeel\u0000 relation, impedance dependence relation, Junjie relation and ideal mixing relation have been used to evaluate ultrasonic velocities in the system under study. The obtained results have been compared with earlier experimental results. The non-ideal behaviour of the mixture has been explained\u0000 in terms of its composition and variation of its acoustical and thermo-dynamical parameters.","PeriodicalId":35085,"journal":{"name":"Acta Acustica united with Acustica","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74577922","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}

引用次数: 4

Sound Radiation from the Perforated End of a Lined Duct 内衬管道穿孔末端的声辐射

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/AAA.919340

B. Tiryakioglu

引用次数: 10

Sound Source Localization Using Head-Related Transfer Functions and Weighted Error Function 基于头部相关传递函数和加权误差函数的声源定位

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/AAA.919346

Sungmok Hwang

引用次数: 1

Broadband Vibrational Energy Harvesting with a Spherical Piezoelectric Transducer Devoted to Underwater Wireless Sensor Networks 用于水下无线传感器网络的球形压电换能器宽带振动能量采集

Acta Acustica united with Acustica Pub Date : 2019-07-01 DOI: 10.3813/AAA.919342

D. Diab, N. Smagin, F. Lefebvre, G. Nassar, S. Isber, F. Omar, A. Naja

{"title":"Broadband Vibrational Energy Harvesting with a Spherical Piezoelectric Transducer Devoted to Underwater Wireless Sensor Networks","authors":"D. Diab, N. Smagin, F. Lefebvre, G. Nassar, S. Isber, F. Omar, A. Naja","doi":"10.3813/AAA.919342","DOIUrl":"https://doi.org/10.3813/AAA.919342","url":null,"abstract":"A new sensing node container based on a spherical piezoelectric transducer is proposed. This device provides broadband vibrational energy harvesting and sensing facilities intended for underwater wireless sensor networks. The transducer is composed of two acrylic glass (PMMA) half-spherical\u0000 shells and a Pz26 piezoelectric ring clamped between the two shells. A simulation model of vibrational energy harvesting has been developed with electromechanical circuits for thickness and radial vibrational modes. This approach was validated by a finite element simulation. As a result, optimal\u0000 power harvesting conditions and estimated harvested voltage were defined. A prototype of 2.2 cm in diameter was realized and characterized. Analysis in air environment reveals several structural resonance modes in the 20–80 kHz frequency range. The directivity patterns corresponding\u0000 to these modes was obtained using laser Doppler vibrometry. The measurements for the underwater environment show that the structural resonance modes shift down in frequency to the 10–60 kHz range, and exhibiting low directivity dependence. Power harvesting performances was measured and\u0000 quantified relative to acoustical pres- sure measurements using a hydrophone. The average conversion coefficient value was found to be in the order of 3 V/MPa. In broadband excitation mode, and for an acoustic pressure of 10 kPa, the amount of harvested power out of 5 main resonance modes\u0000 is 3.3 μW.","PeriodicalId":35085,"journal":{"name":"Acta Acustica united with Acustica","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89379941","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}

引用次数: 3

Piano Strings with Reduced Inharmonicity 减少不谐音的钢琴弦乐

Acta Acustica united with Acustica Pub Date : 2019-06-26 DOI: 10.3813/AAA.919350

J. Dalmont, S. Maugeais

引用次数: 4

Acoustic Plane Wave Scattering from a Soft Finite Truncated Cone in Axial Irradiation 声平面波在软有限截锥轴向辐射中的散射

Acta Acustica united with Acustica Pub Date : 2019-05-10 DOI: 10.3813/AAA.919329

D. Kuryliak, Z. Nazarchuk, Victor Lysechko

引用次数: 1