Journal of Mechanics最新文献_第3页

Downstream influence of turbulent flow past vortex generators 经过涡流发生器的湍流对下游的影响

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-12-05 DOI: 10.1093/jom/ufad039

Y. X. Huang, P. H. Chung, K. M. Chung, C. Y. Huang

引用次数: 0

The CFD Simulation of E1619 Propeller Open Water Tests Validated by the EFD in the NCKU Towing Tank EFD在NCKU拖曳槽中验证的E1619螺旋桨开水试验的CFD模拟

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-11-17 DOI: 10.1093/jom/ufad034

Yu-Hsin Lin, Ahmad Darori Hasan

{"title":"The CFD Simulation of E1619 Propeller Open Water Tests Validated by the EFD in the NCKU Towing Tank","authors":"Yu-Hsin Lin, Ahmad Darori Hasan","doi":"10.1093/jom/ufad034","DOIUrl":"https://doi.org/10.1093/jom/ufad034","url":null,"abstract":"This study established a Computational Fluid Dynamics (CFD) model based on a dynamic mesh strategy to conduct a comprehensive numerical investigation of the performance of the E1619 propeller in open water tests. To capture the turbulence flows around the propeller, a large eddy simulation (LES) turbulence model was implemented. In order to validate the simulation results, a series of open water tests were conducted in the towing tank at National Cheng Kung University, resulting in a successful achievement of total uncertainties of less than approximately 6%. The approach of simultaneous grid and time refinement was utilized to perform the discretization analysis. Eventually, the simulation results were employed to analyze the hydrodynamic performance and flow structure around the propeller, resulting in a conclusion based on the attained level of accuracy. The results indicate that the cases for a propeller with a strut exhibit favorable predictions compared to those of a single propeller, with error values for the thrust coefficients and propeller efficiencies falling below 6%. On the other hand, the torque coefficient was more accurately estimated for the cases of a single propeller than for those of a propeller with a strut, with error values below 2%.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139266200","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

Analytical solutions of free vibration for rectangular thin plate and right-angle triangle plate on the Winkler elastic foundation based on the symplectic superposition method 基于辛叠加法的Winkler弹性地基上矩形薄板和直角三角形板自由振动解析解

4区工程技术

Journal of Mechanics Pub Date : 2023-11-09 DOI: 10.1093/jom/ufad032

Hao-Jie Jiang, Tong-Bo Chen, Yu-Xiang Ren, Ning-Hua Gao

{"title":"Analytical solutions of free vibration for rectangular thin plate and right-angle triangle plate on the Winkler elastic foundation based on the symplectic superposition method","authors":"Hao-Jie Jiang, Tong-Bo Chen, Yu-Xiang Ren, Ning-Hua Gao","doi":"10.1093/jom/ufad032","DOIUrl":"https://doi.org/10.1093/jom/ufad032","url":null,"abstract":"Abstract Based on the symplectic superposition method, the free vibration models of rectangular and right-angle triangle plates on the Winkler elastic foundation are established in present paper, and the modes and frequencies are studied. In addition, the theoretical calculation model and finite element analysis model of rectangular thin plate and right-angle triangle plate on elastic foundation are established by using Mathematica software and ABAQUS software. It proves that the symplectic superposition method converges very fast and has a good consistency with the finite element simulation results. Analytical results show that foundation stiffness, aspect ratio and boundary condition have great influences on vibration frequency and mode shape for structures. This paper solved the free vibration problem of rectangular plate and right-angle triangle plate on elastic foundation by using symplectic superposition method. Compared with the inverse or semi-inverse method, this method avoids the process of assuming the form about the solution, hence the result of this method is completely rational.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135291658","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

Free vibration analysis of Timoshenko pipes conveying fluid with gravity and different boundary conditions 含重力和不同边界条件下输送流体的Timoshenko管道自由振动分析

4区工程技术

Journal of Mechanics Pub Date : 2023-11-09 DOI: 10.1093/jom/ufad031

Bo Shui, Yun-dong Li, Yu-mei Luo, Fei Luo

引用次数: 0

Growth of force chain network upon non-Bagnold Transition of Inclined Surface Granular Flows via Discrete Element Simulation 斜面颗粒流非bagnold过渡时力链网络的增长及其离散元模拟

4区工程技术

Journal of Mechanics Pub Date : 2023-11-09 DOI: 10.1093/jom/ufad030

Cheng-Ting Tsai, Chih-Ying Cheng, F-L Yang

{"title":"Growth of force chain network upon non-Bagnold Transition of Inclined Surface Granular Flows via Discrete Element Simulation","authors":"Cheng-Ting Tsai, Chih-Ying Cheng, F-L Yang","doi":"10.1093/jom/ufad030","DOIUrl":"https://doi.org/10.1093/jom/ufad030","url":null,"abstract":"Abstract A steady granular flow down an inclined surface is an important flow configuration to study the dynamic of dry granular flow. This work adopts two-dimensional discrete element simulation to study how inter-grain friction may play a role in momentum transport, in addition to the collision-based transport, to induce the non-Bagnold flow velocity profile reported in the literature. Special efforts were made to apply the knowledge of network science to identify the contact force chain network from particle dynamics information using the graph theory with the Louvain greedy algorithm. We studied how the number of grains born in the force chain network grows when the flow scaled velocity profile degrades from Bagnold to non-Bagnold flows. Concurrently, the stress loading ratio carried by these frictional contacts rises abruptly upon the non-Bagnold flow transition identifies when the flow Froude number falls roughly below 2.15. Both phenomena suggest that the non-local phenomenon of Bagnold velocity profile degradation occurs when sufficient grains are confined in the force chain network to assist the stress transport, replacing the collisional transport. Hence, a refined rheology model is needed in the future to account for this friction-assisted momentum transport at a mesoscopic yet flow-dependent length scale like that of the currently investigated force network.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135291659","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

Flow and heat transfer characteristics in fallopian tube with metachronal wave of cilia 纤毛异向波作用下输卵管内流动和换热特性

4区工程技术

Journal of Mechanics Pub Date : 2023-10-13 DOI: 10.1093/jom/ufad027

Anum Tanveer, Zain Ul Abidin, Faisal Z Duraihem, S Saleem

引用次数: 0

Jetting and shock wave during oblique hypervelocity impact of spherical projectile 球面弹丸倾斜超高速撞击时的射流与激波

4区工程技术

Journal of Mechanics Pub Date : 2023-09-13 DOI: 10.1093/jom/ufad012

Xin Liu, Yongjun Deng, Ken Wen, Yong Yao

{"title":"Jetting and shock wave during oblique hypervelocity impact of spherical projectile","authors":"Xin Liu, Yongjun Deng, Ken Wen, Yong Yao","doi":"10.1093/jom/ufad012","DOIUrl":"https://doi.org/10.1093/jom/ufad012","url":null,"abstract":"Abstract Space debris impacts on whipped shields are dominantly non-vertical. Shock initiation and interaction govern the fragmentation of projectiles and plates, directly determining the features of the produced debris cloud. During the initial impact stage of a projectile on a target, wave propagation and evolution occur in their interior with co-dominant material fragmentation. In this study, the effects of the impact conditions (impact velocity and attack angle) on the critical conditions for jet generation were examined based on the asymmetric jetting theory. In the Geometric Propagation Model (GPM), the effect of the attack angle was considered, and a wave front deflection angle parameter was introduced. The modified GPM could describe the geometric features and position of a wave front during an oblique impact. Combined with smoothed particle hydrodynamics numerical simulations, the interior of projectiles, fragmentation features, and pressure attenuation were studied. It was found that in large attack angle cases, the projectile material is more likely to reach the critical conditions for jet generation, and the jet mass proportion of the projectile material increases with increasing attack angle. The modified GPM is an oblique elliptic Eq. that is a function of the equivalent speed, impact velocity, attack angle, time, and deflection angle. It may be applicable to hypervelocity events involving any monolithic material as long as the equivalent speed and deflection angle can be provided from numerical simulations. The impact conditions exhibit a quantitative relationship with the pressure attenuation in a projectile, among which the impact velocity has a more significant effect. This study established a quantitative analysis method for initial impact stage of the oblique hypervelocity impact of a spherical projectile on a flat plate.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135785988","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

Temperature-Dependence Mechanical Characteristics Investigation of Cu Wire and Corresponding High Strain Rate Plasticity Behaviors Enabled by Johnson-Cook Constitutive Model 基于Johnson-Cook本构模型的铜丝温度依赖力学特性及高应变率塑性行为研究

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-08-11 DOI: 10.1093/jom/ufad020

De-Shin Liu, Po-Chun Wen, Z. Zhuang, Y. Chao, Pei-Chen Huang

引用次数: 0

Nonlinear Ultrasonic Characterization of Joint Structures Using Backscatter Guided Waves 基于后向散射导波的关节结构非线性超声表征

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-08-10 DOI: 10.1093/jom/ufad022

Wenqiu Wu, C. Yin

{"title":"Nonlinear Ultrasonic Characterization of Joint Structures Using Backscatter Guided Waves","authors":"Wenqiu Wu, C. Yin","doi":"10.1093/jom/ufad022","DOIUrl":"https://doi.org/10.1093/jom/ufad022","url":null,"abstract":"\u0000 Joint structures made from plates or shells are frequently used in large constructions, such as oil storage tanks in petrochemical industries. The corrosion-induced metal loss often appears on the back side of the bottom plate supported by ground or sand. The welding residual stress and weight of shell walls accelerate the corrosion. Determining the severity of metal loss under the joint is challenging. This work uses the mode pair technique for nondestructive inspection of inaccessible regions in joint structures. A finite element analysis model simulates the transient responses of the incident and mode-converted fundamental and second harmonic plate waves. The second harmonic s0 plate wave satisfying the phase velocity matching condition accompanies the transmitted fundamental SH0 plate wave. A directional filter identifies every mode-converted plate wave by comparing the frequency spectra with the dispersion curves. Linear ultrasonic guided waves can detect inaccessible regions using mode-converted reflections. The symmetry of the linear mode-converted fundamental plate waves depends on the defect position and geometry, not the size. The mode-converted second harmonic guided wave can achieve better spatial resolution for defect sizing. The nonlinear parameter shows a proportional trend with an increasing thickness reduction. Experimental and numerical evidence reveals nonlinear ultrasonic guided wave technique has the potential for defect detection in joint structures.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42524555","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

Thermal Performance of Open Microchannel Heat Sink with NACA Airfoil Shaped PIN Fins NACA翼型PIN翅片开放式微通道散热器的热性能

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-08-10 DOI: 10.1093/jom/ufad019

Kun-Da Wu, H. Weng

{"title":"Thermal Performance of Open Microchannel Heat Sink with NACA Airfoil Shaped PIN Fins","authors":"Kun-Da Wu, H. Weng","doi":"10.1093/jom/ufad019","DOIUrl":"https://doi.org/10.1093/jom/ufad019","url":null,"abstract":"\u0000 The main purpose of this study is to numerically investigate the effect of pin-fin NACA airfoil on the heat transfer performance of a single open microchannel heat sink with a fixed surface area and a constant wall heat flux. It was found that the helical flow within the microchannel and the converging-diverging flow near the two sides of the microchannel, caused by the periodically arranged NACA airfoil shaped pin fins with an attack angle, dominate the overall heat dissipation ability of the heat sink. The heat dissipation ability can be further improved by increasing the attack angle and Reynolds number. Of the airfoils considered, the symmetrical airfoil NACA0012 in no attack angle case presents the smallest pressure drop, but also the smallest thermal performance value, which can still achieve a Nusselt number improvement of 35.15% and a thermal performance factor (TPF) improvement of 1.38%, compared to the no-fin case. The NACA airfoil effect can be improved when asymmetric airfoils are considered. In terms of overall thermal performance, the NACA6412 would be the best choice. Its percentage increases in the Nusselt number and TPF can be further enhanced by up to 57.62% and 35.43%, respectively, compared to the no-attack-angle NACA0012 case.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49622826","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