Journal of Sound and Vibration最新文献_第5页

Influence of angle of attack on airfoil tip noise 迎角对翼型尖噪声的影响

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-27 DOI: 10.1016/j.jsv.2025.119376

Guang C. Deng , Satoshi Baba , Philippe Lavoie , Stéphane Moreau

{"title":"Influence of angle of attack on airfoil tip noise","authors":"Guang C. Deng , Satoshi Baba , Philippe Lavoie , Stéphane Moreau","doi":"10.1016/j.jsv.2025.119376","DOIUrl":"10.1016/j.jsv.2025.119376","url":null,"abstract":"<div><div>This study investigates the aerodynamic and aeroacoustic characteristics of airfoil tip noise for a supercritical airfoil profile at <span><math><mrow><mi>α</mi><mo>=</mo><mn>5</mn><mo>°</mo></mrow></math></span> and <span><math><mrow><mi>α</mi><mo>=</mo><mn>10</mn><mo>°</mo></mrow></math></span> using a hybrid noise computation approach. Wall-Resolved Large Eddy Simulations (WR-LES) were performed and validated against experimental data from the University of Toronto. The simulations captured a tri-vortex system (TVS) comprising primary, secondary, and tertiary vortices. At <span><math><mrow><mi>α</mi><mo>=</mo><mn>10</mn><mo>°</mo></mrow></math></span>, upstream shifts in the primary vortex trajectory intensified interactions with the airfoil surface, resulting in amplified surface-pressure fluctuations and increased far-field noise levels. Dynamic Mode Decomposition (DMD) pinpoints dominant acoustic sources and their radiation patterns, distinguishing between duct acoustic modes below 1500 Hz and localized sources above this frequency with clear dipole radiation patterns stemming from three noise sources: the leading-edge, trailing-edge, and side-edge noise. The far-field acoustic predictions, computed using the Ffowcs Williams–Hawkings (FW-H) analogy, showed good agreement with experimental results. Both the solid and porous FW-H formulations accurately captured noise levels, with a 3 dB increase in spectral levels observed at <span><math><mrow><mi>α</mi><mo>=</mo><mn>10</mn><mo>°</mo></mrow></math></span> due to enhanced aerodynamic loading and vortex dynamics. Noise decomposition showed a shift in dominant sources: trailing-edge noise prevailed at <span><math><mrow><mi>α</mi><mo>=</mo><mn>5</mn><mo>°</mo></mrow></math></span>, while tip noise, driven by vortex impingement and crossover, dominated at <span><math><mrow><mi>α</mi><mo>=</mo><mn>10</mn><mo>°</mo></mrow></math></span>, highlighting the complex aerodynamic-acoustic interplay.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"620 ","pages":"Article 119376"},"PeriodicalIF":4.9,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Adjoint computation of Berry phase gradients Berry相位梯度的伴随计算

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-27 DOI: 10.1016/j.jsv.2025.119357

Cyrill Bösch , Marc Serra-Garcia , Christian Böhm , Andreas Fichtner

{"title":"Adjoint computation of Berry phase gradients","authors":"Cyrill Bösch , Marc Serra-Garcia , Christian Böhm , Andreas Fichtner","doi":"10.1016/j.jsv.2025.119357","DOIUrl":"10.1016/j.jsv.2025.119357","url":null,"abstract":"<div><div>Berry phases offer a geometric perspective on wave propagation and are key to designing materials with topological wave transport. However, controlling Berry phases is challenging due to their dependence on global integrals over the Brillouin zone, making differentiation difficult. We present an adjoint-based method for efficiently computing the gradient of the Berry phase with respect to system parameters. We introduce an adjoint-based algorithm that computes Berry-phase gradients via only one forward and one adjoint solve. Under reasonable assumptions the algorithm’s time complexity is <span><math><mrow><mi>O</mi><mrow><mo>(</mo><msup><mrow><mi>N</mi></mrow><mrow><mn>1</mn><mo>+</mo><mn>1</mn><mo>/</mo><mi>D</mi></mrow></msup><mo>)</mo></mrow></mrow></math></span>, where <span><math><mi>N</mi></math></span> is number of grid points in a numerical discretization scheme and <span><math><mi>D</mi></math></span> is the space dimension. Thereby it outperforms numerical differentiation and perturbation theory for problems with a large number of design variables. This approach enables the use of advanced, gradient-based optimization techniques to design new continuously parameterized materials with tailored topological wave properties. Furthermore, via multi-objective optimizations this method allows to co-design the topological characteristics in tandem with other objectives. We apply the method to an elastic metamaterial rod.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119357"},"PeriodicalIF":4.9,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Viscoelastic foundation-induced vibrations: Exploring linear theory application fields through numerical simulations 粘弹性地基诱发振动：通过数值模拟探索线性理论的应用领域

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-26 DOI: 10.1016/j.jsv.2025.119415

Simone De Carolis , Carmine Putignano , Leonardo Soria , Giuseppe Carbone

{"title":"Viscoelastic foundation-induced vibrations: Exploring linear theory application fields through numerical simulations","authors":"Simone De Carolis , Carmine Putignano , Leonardo Soria , Giuseppe Carbone","doi":"10.1016/j.jsv.2025.119415","DOIUrl":"10.1016/j.jsv.2025.119415","url":null,"abstract":"<div><div>This study investigates the dynamic interaction between a massive rigid body and a viscoelastic, non-adhesive flat substrate, behaving as a moving unilateral foundation and, thus, oscillating under various kinematic conditions (stationary sinusoidal, time-varying harmonic, and stochastic excitation). Such a problem is reduced to an equivalent single-degree-of-freedom base-excited system, where the intricate contact interactions involving the oscillating viscoelastic foundation are assessed by introducing a complex dynamic contact stiffness. This model is intrinsically linear and is based on the assumption that variations in the contact area, relative to the contact length in the static equilibrium configuration, may be neglected. Special attention is given to the phenomena of tapping, that is, the contact separation: the latter is clearly related to the amplitude and frequency of the foundation oscillations. An analytical relation, derived within the linear framework, is obtained to predict the incipient tapping front. To establish the application fields of this linear approach, we implement a Boundary Element Method (BEM)-based model that calculates the contact force, iteratively coupling the contact problem with the dynamic equation of the rigid supported mass. The results confirm that the linear model provides accurate predictions for transmissibility and the separation front under low-amplitude oscillations. For higher amplitudes, a specific frequency range emerges, characterized by tapping mode, thereby verifying the model’s capacity to delineate regions of continuous contact and tapping mode. Additionally, under non-stationary excitation conditions, the linear theory effectively predicts the transitions between contact and separation phases.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119415"},"PeriodicalIF":4.9,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Design of piezoelectric metastructures with multi-patch isogeometric analysis for enhanced energy harvesting and vibration suppression 基于多片等几何分析的压电元结构设计增强能量收集和振动抑制

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-26 DOI: 10.1016/j.jsv.2025.119401

P. Peralta-Braz , M.M. Alamdari , M. Hassan , E. Atroshchenko

{"title":"Design of piezoelectric metastructures with multi-patch isogeometric analysis for enhanced energy harvesting and vibration suppression","authors":"P. Peralta-Braz , M.M. Alamdari , M. Hassan , E. Atroshchenko","doi":"10.1016/j.jsv.2025.119401","DOIUrl":"10.1016/j.jsv.2025.119401","url":null,"abstract":"<div><div>Metastructures are engineered systems composed of periodic arrays of identical components, called resonators, designed to achieve specific dynamic effects, such as creating a bandgap-a frequency range where waves cannot propagate through the structure. When equipped with patches of piezoelectric material, these metastructures exhibit an additional capability: they can harvest energy effectively even from frequencies much lower than the fundamental frequency of an individual resonator. This energy harvesting capability is particularly valuable for applications where low-frequency vibrations dominate. To support the design of metastructures for dual purposes, such as energy harvesting and vibration suppression (reducing unwanted oscillations in the structure), we develop a multi-patch isogeometric model of a piezoelectric energy harvester. This model is based on a piezoelectric Kirchhoff–Love plate – a thin, flexible structure with embedded piezoelectric patches – and uses Nitsche’s method to enforce compatibility conditions in terms of displacement, rotations, shear force, and bending moments across the boundaries of different patches. The model is validated against experimental and numerical data from the literature. We then present a novel, parameterised metastructure plate design and conduct a parametric study to explore how resonator geometries affect key performance metrics, including the location and width of the band gap and the position of the first peak in the voltage frequency response function. This model can be integrated with optimisation algorithms to maximise outcomes such as energy harvesting efficiency or vibration reduction, depending on application needs.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119401"},"PeriodicalIF":4.9,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144921396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Active vibration control of elastically restrained rotating beams with piezoelectric patches placement optimization 基于压电片位置优化的弹性约束旋转梁振动主动控制

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-25 DOI: 10.1016/j.jsv.2025.119426

Xiaohu Ma, Zhu Su

{"title":"Active vibration control of elastically restrained rotating beams with piezoelectric patches placement optimization","authors":"Xiaohu Ma, Zhu Su","doi":"10.1016/j.jsv.2025.119426","DOIUrl":"10.1016/j.jsv.2025.119426","url":null,"abstract":"<div><div>This paper establishes a dynamic model of an elastically restrained rotating beam equipped with piezoelectric sensors/actuators, and the ability to actively control vibrations of this beam subjected to mixed excitation with optimization of the placement of piezoelectric patches is investigated. The elastic boundary conditions are simulated via the artificial spring technique, and the stiffening effect resulting from rotation motion is considered by adding potential energy due to the centrifugal force. The displacement field is expanded using the modified Fourier series method, and the system governing equations are derived through the Lagrange equations. On the basis of the controllability Gramian matrix, the placement of piezoelectric sensors/actuators is optimized for the first two flapwise modal vibrations and their combination, and the effects of boundary stiffness and rotational speed on the optimization results and corresponding control performance are studied. The results indicate that the linear spring stiffness significantly influences the optimization results, whereas the torsional spring stiffness and rotational speed have little effect on the optimization results. Finally, a vibration control experiment was conducted on a rotating beam to verify the correctness and effectiveness of the proposed control system.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119426"},"PeriodicalIF":4.9,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144916397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Structural K-space identification via ambient noise and its application to passive ice detection 基于环境噪声的结构k空间识别及其在被动冰探测中的应用

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-24 DOI: 10.1016/j.jsv.2025.119403

Qihang Qin , Xun Wang , Mohamed Ichchou , Thomas Brion

{"title":"Structural K-space identification via ambient noise and its application to passive ice detection","authors":"Qihang Qin , Xun Wang , Mohamed Ichchou , Thomas Brion","doi":"10.1016/j.jsv.2025.119403","DOIUrl":"10.1016/j.jsv.2025.119403","url":null,"abstract":"<div><div>Ambient noise measured by a small number of receivers is used to identify the complex-valued wavenumber trajectory, known as the K-space, of a thin-wall structure. Its real and imaginary parts correspond to the dispersion and attenuation curves, which both include important information about structural health conditions. A sensor placement strategy with unequal spacings is proposed to optimize the spatial sampling. The cross-correlation between the random ambient noise measured by each pair of sensors is computed to estimate the structural impulse response, after performing a post-processing of whitening and coda wave elimination. The wavenumber trajectory of K-space is then estimated by matching the refined cross-correlation with the Green’s function of the wave equation. Experimental results with various flow-induced or mechanical vibration excitations from a household hairdryer to an axial flow fan justify the robustness of the proposed method, where no more than eight receivers are required. An application of icing detection is presented, where the dispersion curve shift and wave energy attenuation due to ice accretion on a thin-wall structure are respectively captured by the estimated real and imaginary parts of the K-space. As a result, ice thickness estimation and icing warning algorithms are both explicitly given.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119403"},"PeriodicalIF":4.9,"publicationDate":"2025-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

A method to investigate the influence of geometry parameters on the vibroacoustic behavior of Kelvin cell foam 一种研究几何参数对开尔文孔泡沫振声特性影响的方法

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-23 DOI: 10.1016/j.jsv.2025.119405

Zenong Cai , Vicente Cutanda Henrìquez , Aminul Islam , Frieder Lucklum

引用次数: 0

Intrinsic aeroacoustic instabilities in the crosstalk apertures of can-annular combustors 罐环燃烧室串扰孔径的固有气动声学不稳定性

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-22 DOI: 10.1016/j.jsv.2025.119366

Audrey Blondé, Khushboo Pandey, Bruno Schuermans, Nicolas Noiray

{"title":"Intrinsic aeroacoustic instabilities in the crosstalk apertures of can-annular combustors","authors":"Audrey Blondé, Khushboo Pandey, Bruno Schuermans, Nicolas Noiray","doi":"10.1016/j.jsv.2025.119366","DOIUrl":"10.1016/j.jsv.2025.119366","url":null,"abstract":"<div><div>This paper presents an experimental and numerical study of aeroacoustic instabilities at the interface between neighbouring combustion chambers in modern heavy-duty gas turbines. A simplified laboratory-scale geometry of the gap separating the outlet of these chambers, just upstream of the turbine inlet in can-annular combustor architectures, is considered. It consists of two channels with anechoic and choked conditions on the upstream and downstream sides, respectively. Right before the choked-flow vanes which represent the turbine inlet, a small aperture leads to an aeroacoustic crosstalk between the channels. The dimensions and flow conditions are defined such that relevant Mach, Strouhal and Helmholtz numbers of gas turbines are reproduced. The alignment of the vanes with respect to the crosstalk aperture is varied. An intense whistling is observed for some conditions. The oscillation frequency depends on the aperture area and scales with the Strouhal number based on the aperture length. The upstream anechoic condition in each channel implies that no longitudinal acoustic mode participates to the mechanism of this whistling, which is in agreement with the Strouhal scaling of this intrinsic aeroacoustic instability. It is shown that the geometry of the upstream edge of the aperture is an essential element in the occurrence and intensity of the whistling. Compressible Large Eddy Simulations of the configuration have been performed and remarkably reproduce the whistling phenomenon. A detailed investigation of the numerical results revealed the region of sound production from the shear layer oscillations in the crosstalk aperture. This work contributes to the understanding of aeroacoustic instabilities at the crosstalk apertures of can-annular combustors. It will help designing combustor–turbine interfaces to suppress them, which is important since the vibrations they induce may be as damaging as those from thermoacoustic instabilities.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119366"},"PeriodicalIF":4.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Modelling high-frequency tyre belt vibrations 模拟高频轮胎皮带振动

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-21 DOI: 10.1016/j.jsv.2025.119393

W.R. Graham

{"title":"Modelling high-frequency tyre belt vibrations","authors":"W.R. Graham","doi":"10.1016/j.jsv.2025.119393","DOIUrl":"10.1016/j.jsv.2025.119393","url":null,"abstract":"<div><div>The problem of tyre noise demands, among other approaches, theoretical prediction methods. A key component here is calculation of the tyre vibrations. A tyre is a complex, composite structure, especially the belt. The majority of work to date has treated this component as a thin plate, which is advantageous for computational economy. However, the fidelity of the representation is unclear, as is its relation to the belt’s component material properties. Here, these questions are addressed in the context of a problem for which exact solutions can be computed: wave propagation on a planar laminate matching the belt’s composition. Over most of the frequency range of interest — up to 2 kHz — three waves can be sustained: flexural, horizontal-shear and extensional. Approximate solutions have been obtained on the basis of the Kirchhoff and Reissner–Mindlin assumptions, layerwise polynomial expansions, and a one-dimensional finite-element discretisation. The thin-plate (Kirchhoff and Reissner–Mindlin) approaches fail to reproduce the exact solutions satisfactorily. In contrast, the methods that resolve the laminate thickness are able to do so, but need high resolutions to capture the horizontal-shear wave accurately. This observation has significant implications for the numerical cost of tyre-noise simulation, and suggests that further work on developing simplified formulations is needed.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119393"},"PeriodicalIF":4.9,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144913787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Training Structures as Distributed Sensors: A case study of impact force identification using neural operators 训练结构作为分布式传感器：使用神经算子进行冲击力识别的案例研究

IF 4.9 2区工程技术

Journal of Sound and Vibration Pub Date : 2025-08-19 DOI: 10.1016/j.jsv.2025.119395

Yujie Gan , Haoze Song , Zhilu Lai

{"title":"Training Structures as Distributed Sensors: A case study of impact force identification using neural operators","authors":"Yujie Gan , Haoze Song , Zhilu Lai","doi":"10.1016/j.jsv.2025.119395","DOIUrl":"10.1016/j.jsv.2025.119395","url":null,"abstract":"<div><div>Structural sensing data not only provides insights into a structure’s behaviors but also contains valuable information about its surrounding environments. The concept of “Structures as Sensors” has introduced the idea of enabling structures to be environment-aware and serve as a sensing platform. In this paper, we propose extending this concept to “structures as distributed sensors” (S2DS), utilizing learning-based methods to infer surrounding environments from structural vibration data. Our approach addresses the challenge of perceiving environmental events not present in the training dataset, particularly highlighting high-resolution solutions – providing solutions across densely distributed locations, with limited deployed sensors. As a proof of concept for S2DS, we present a study on impact force identification using Fourier Neural Operator (FNO) with a proposed spatial upsampling mechanism. FNO is designed to infer spatiotemporal source functions from structural responses, allowing for the simultaneous localization and reconstruction of impact forces within a unified framework. We also use a continuous distribution representation of single-point impact forces, which effectively tackles the issue of training on highly sparse data while ensuring precise localization. The validation of our framework on a cantilever beam and a wind turbine blade demonstrates accurate identification of both the location and time history of impact forces, irrespective of the localization resolution. Importantly, our framework delivers satisfactory outcomes with a limited training dataset, highlighting its potential for structural health monitoring and environmental perception of engineering structures in various scenarios with limited sensors and training resources.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"619 ","pages":"Article 119395"},"PeriodicalIF":4.9,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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