Journal of Fluids and Structures最新文献

Scattering of oblique incident waves by a rigid floating structure in the presence of two surface-piercing thick porous breakwaters: Pattern of reflection, dissipation and wave forces

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-03-06 DOI: 10.1016/j.jfluidstructs.2025.104285

Shilpi Jain, Swaroop Nandan Bora

{"title":"Scattering of oblique incident waves by a rigid floating structure in the presence of two surface-piercing thick porous breakwaters: Pattern of reflection, dissipation and wave forces","authors":"Shilpi Jain, Swaroop Nandan Bora","doi":"10.1016/j.jfluidstructs.2025.104285","DOIUrl":"10.1016/j.jfluidstructs.2025.104285","url":null,"abstract":"<div><div>The present work examines the wave interaction with a rigid floating structure, placed after two distinct porous structures, to mitigate wave-induced forces acting on the floating structure. The physical and mathematical consideration of the wave passing through these thick porous structures is based on the model devised by Sollitt and Cross (1972). Splitting the fluid domain into nine regions, the scattered potential in each region is obtained by setting up a system of equations using the relevant matching conditions across the boundaries. The behavior of the roots of the dispersion relation is analyzed to identify conditions under which the eigenfunction solution may become invalid. The graphs plotted for the reflection coefficient, transmission coefficient, dissipation coefficient, and wave-induced forces acting on the floating structure indicate several findings: (i) if the porosity of the second porous structure is less than that of the first porous structure, then the wave energy loss increases, thereby enhancing the safety of the floating structure through reduction of the forces, (ii) as the value of the friction factor of both breakwaters increases, the reflection coefficient decreases, (iii) by increasing the height and thickness of the breakwaters, more loss of wave energy can be achieved due to the dissipative nature of the porous structures. Consequently, the forces acting on the floating structure decrease, helping in its stability. The findings propose the appropriate values of different parameters for an efficient design of such porous breakwaters, as well as how they need to be located.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"135 ","pages":"Article 104285"},"PeriodicalIF":3.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551609","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

Visualization and measurement of shock movement during transonic limit-cycle oscillation

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-27 DOI: 10.1016/j.jfluidstructs.2025.104278

Eric D. Stubblefield , Donald L. Kunz , Nicholas W. Dona

引用次数: 0

Data assimilation for turbulence-merged channel branches with the simultaneous enhancement of hydrodynamics and aeroacoustics

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-25 DOI: 10.1016/j.jfluidstructs.2025.104283

Peng Wang , Xu Qiang , Hyung Jin Sung , Yingzheng Liu

{"title":"Data assimilation for turbulence-merged channel branches with the simultaneous enhancement of hydrodynamics and aeroacoustics","authors":"Peng Wang , Xu Qiang , Hyung Jin Sung , Yingzheng Liu","doi":"10.1016/j.jfluidstructs.2025.104283","DOIUrl":"10.1016/j.jfluidstructs.2025.104283","url":null,"abstract":"<div><div>This study explored the dynamic interplay between turbulent flow and transverse duct acoustic modes within intersecting channel branches containing two inlet branches and one outlet channel, motivated by the experimental findings of Ziada et al., 2009, entitled “Flow-acoustic coupling in T-junctions: effect of T-junction geometry” in J<em>. Press. Vessel Technol.</em> 131(4) and the work of Salt et al. 2014, entitled “Aeroacoustic sources generated by flow–sound interaction in a T-junction” in J<em>. Fluid. Struct.</em> 51, 116–131. We specifically examined how this interaction led to the simultaneous enhancement of both hydrodynamic and aeroacoustic characteristics. Compressible large eddy simulation (LES) was implemented to solve the compressible Navier–Stokes equations, and a data-assimilated momentum loss model with physical constraints was incorporated to enhance the LES accuracy and obtain the self-sustained flow–acoustic resonance fields. We further focused on the influences of upstream flow separation on the excited resonance behaviors. The numerical results with a data-assimilation strategy agreed well with the literature and acoustic modal analysis in terms of frequency, amplitude, and fundamental waveform. Three types of unsteady flow events, characterized by shear layers, recirculation zones, and separation bubbles, were identified in close response to the excited acoustic eigenmodes. The dynamics, including the acoustic-phase-resolved spatiotemporal evolution, kinematics, such as the convection trajectory and speed, and energetics, such as the aeroacoustic power sources, were further elucidated. The vertical Coriolis force, which was influenced by the secondary separation bubbles, along with the horizontal acoustic particle velocity, played a significant role in the generation of aeroacoustic power.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"134 ","pages":"Article 104283"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487078","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

Experimental investigation in nonlinear aerodynamic characteristics of a double-layer truss girder

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-24 DOI: 10.1016/j.jfluidstructs.2025.104284

Jiankun Li , Cunming Ma , Bo Wu , Ding Zeng

{"title":"Experimental investigation in nonlinear aerodynamic characteristics of a double-layer truss girder","authors":"Jiankun Li , Cunming Ma , Bo Wu , Ding Zeng","doi":"10.1016/j.jfluidstructs.2025.104284","DOIUrl":"10.1016/j.jfluidstructs.2025.104284","url":null,"abstract":"<div><div>This study investigated the nonlinear aerodynamic characteristics of a double-layer truss girder at various angles of attack (AoAs) through section model wind tunnel tests. The free vibration test revealed a divergent hard flutter of the girder at 0° AoA and a self-limiting soft flutter of the girder at +3° and +5° AoAs, with responses primarily dominated by the fundamental frequency. The forced vibration test detected significant high-order harmonic components in the aerodynamic forces. Analysis of the hysteresis loops of each decomposed high-order harmonic affirmed the modification of these components on the system's energy exchange behavior over time, but refuted their impact on the occurrence of a limit cycle oscillation (LCO). Conversely, the consistency in the sign changes of the dimensionless aerodynamic work and the phase lag of the linear self-excited-moment to the torsional motion underscores the critical role of the phase difference in the occurrence of soft flutter and LCO. At last, the macroscopic energy distribution of the girder in different degrees of freedom (DOF) varies with amplitude and wind speed was quantified in terms of the three-dimensional (3D) energy map, which confirmed the consistency between the free and forced vibration tests on the section. This also revealed the fundamental mechanisms behind instability hysteresis and aerodynamic discrepancies under different DOF and AoAs.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"134 ","pages":"Article 104284"},"PeriodicalIF":3.4,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474755","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

Impact of a porous structure placed at the sea-bed in wave scattering around ice floes

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-23 DOI: 10.1016/j.jfluidstructs.2025.104280

Saniya Suhail , Sunanda Saha , Koushik Kanti Barman , Swaroop Nandan Bora

{"title":"Impact of a porous structure placed at the sea-bed in wave scattering around ice floes","authors":"Saniya Suhail , Sunanda Saha , Koushik Kanti Barman , Swaroop Nandan Bora","doi":"10.1016/j.jfluidstructs.2025.104280","DOIUrl":"10.1016/j.jfluidstructs.2025.104280","url":null,"abstract":"<div><div>The present work examines the two-dimensional wave scattering problem involving a pair of ice floes of finite length separated by a finite gap over a finite ocean depth with a thick porous structure lying on an impermeable sea-bed. The physical and mathematical considerations of wave propagation through thick porous structures are analysed by analysing the interaction between the wave and the porous medium. Following linear water wave theory, the boundary value problem (BVP) is solved using the matched eigenfunction expansion method. Numerical results on various hydrodynamic coefficients are presented by varying the parameters pertaining to the porous structure and the ice floe. The reflection coefficient oscillates with an increase in the length of the first floe in the direction of the incoming waves and settles down when the length of the second floe increases. Maximum transmission is experienced when the gap between the two floes is substantial, since a higher gap allows more waves to pass through, thereby increasing the rate of transmission. The present study shows that an increase in the porosity shifts the phase of the maximum reflection, whereas a thick porous structure diminishes the maximum reflection coefficient by absorbing wave energy. With an increase in rigidity, the reflection coefficient increases, and at higher compressive force, the energy absorption increases, and consequently, the reflection reduces.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"134 ","pages":"Article 104280"},"PeriodicalIF":3.4,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471403","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

Unified meshfree-spectral BEM model for acoustic radiation analysis of double-walled coupled shells

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-21 DOI: 10.1016/j.jfluidstructs.2025.104279

Xianjie Shi, Xikai Li, Zhou Huang, Qiang Wan

{"title":"Unified meshfree-spectral BEM model for acoustic radiation analysis of double-walled coupled shells","authors":"Xianjie Shi, Xikai Li, Zhou Huang, Qiang Wan","doi":"10.1016/j.jfluidstructs.2025.104279","DOIUrl":"10.1016/j.jfluidstructs.2025.104279","url":null,"abstract":"<div><div>A unified mathematical model for acoustic radiation responses of laminated composite double-walled coupled shells with bulkheads immersed in an unbounded light and heavy fluid environments is established by utilizing unified meshfree-spectral BEM (boundary element method). In order to ensure the stability and reliability of the numerical solution, the mathematical model is divided into several hyperbolic curves, cylindrical shells and ring plates. Different types of the doubly-curved shell are considered such as elliptical and paraboloidal shells. By analyzing the geometrical relationship of double-walled shell, the displacement continuous boundary conditions between adjacent segment interfaces are determined. The structural field and external acoustic field of a double-walled shell are derived by using the energy principle in framework of first-order shear deformation theory and Kirchhoff-Helmholtz integral formulation respectively. The numerical example shows that the mathematical model can be used to solve the acoustic radiation response of the double-walled coupled shell in the acoustic fluid medium. Finally, the effects of representative parameters such as geometry, acoustic fluid medium, boundary conditions and external load on the acoustic radiation characteristics of double-walled shells are systematically discussed, which provides useful information for the design of light and heavy fluid double-walled structures.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"134 ","pages":"Article 104279"},"PeriodicalIF":3.4,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453699","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

Stability analysis of an articulated flexible pipe conveying fluid with a rotational spring

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-20 DOI: 10.1016/j.jfluidstructs.2025.104277

Yikun Wang , Jianhang Lv , Mo Yang , Yang Zhang , Tao Qin , Lin Wang

{"title":"Stability analysis of an articulated flexible pipe conveying fluid with a rotational spring","authors":"Yikun Wang , Jianhang Lv , Mo Yang , Yang Zhang , Tao Qin , Lin Wang","doi":"10.1016/j.jfluidstructs.2025.104277","DOIUrl":"10.1016/j.jfluidstructs.2025.104277","url":null,"abstract":"<div><div>The stability of an articulated flexible pipe conveying fluid by altering its structural parameters is investigated in this paper. Utilizing generalized Hamilton's principle, the governing equations for the motion of both the upper and lower pipe segments of the system are established. The equations are then discretized using the Galerkin's method, which leads to a generalized eigenvalue problem. To validate the mathematical model, the eigenvalue branches of a degenerated system are compared with prior findings by using extreme values for the structural parameters. The results indicate that the instability characteristics of the pipe system are heavily influenced by these parameters. A reduction in the length of the upper segment causes the system to exhibit characteristics similar to either a pinned-free or cantilevered pipe, contingent upon the stiffness of the rotational spring. Secondary flutter phenomena manifest after the third or fourth mode instability as the flow velocity increases. When the upper and lower segments are of equal lengths, the critical flow velocity stabilizes when the spring stiffness surpasses a certain threshold. The inclusion of a flexible joint between the segments increases the system's susceptibility to higher-mode instability. Additionally, an extended upper segment may result in intricate instability behaviors, including a sequence of “instability-restabilization-instability” as the flow velocity rises. These innovative numerical findings provide theoretical perspectives on the dynamic behavior of articulated fluid-conveying pipes.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"133 ","pages":"Article 104277"},"PeriodicalIF":3.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444725","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 data-driven approach for modeling large-amplitude flow-induced oscillations of elastically mounted pitching wings

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-20 DOI: 10.1016/j.jfluidstructs.2025.104282

Yuanhang Zhu , Kenneth Breuer

{"title":"A data-driven approach for modeling large-amplitude flow-induced oscillations of elastically mounted pitching wings","authors":"Yuanhang Zhu , Kenneth Breuer","doi":"10.1016/j.jfluidstructs.2025.104282","DOIUrl":"10.1016/j.jfluidstructs.2025.104282","url":null,"abstract":"<div><div>We propose and validate a data-driven approach for modeling large-amplitude flow-induced oscillations of elastically mounted pitching wings. We first train a neural networks regression model for the nonlinear aerodynamic moment using data obtained from experimental measurements during prescribed pitching oscillations and at fixed angles of attack. We then embed this model into an ordinary differential equation solver to solve the governing equation of the passive aeroelastic system with desired structural parameters. The system dynamics predicted by the proposed data-driven approach are characterized and compared with those obtained from physical experiments. The predicted and experimental pitching amplitude, frequency and aerodynamic moment responses are found to be in excellent agreement. Both the inertia-dominated mode and the hydrodynamic-dominated mode are successfully predicted. The transient growth and saturation of the pitching oscillation amplitude and the aerodynamic moment are also faithfully captured by the proposed approach. Additional test cases demonstrate the broad applicability and good scalability potential of this approach.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"134 ","pages":"Article 104282"},"PeriodicalIF":3.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Prediction of clamped–clamped elastic panel motion under influence of shock-wave turbulent boundary layer interactions using WMLES with a 3D aeroelastic solver

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-20 DOI: 10.1016/j.jfluidstructs.2025.104281

Chelsea Johnson , Luisa Piccolo Serafim , Joseph C. Oefelein , Earl H. Dowell

{"title":"Prediction of clamped–clamped elastic panel motion under influence of shock-wave turbulent boundary layer interactions using WMLES with a 3D aeroelastic solver","authors":"Chelsea Johnson , Luisa Piccolo Serafim , Joseph C. Oefelein , Earl H. Dowell","doi":"10.1016/j.jfluidstructs.2025.104281","DOIUrl":"10.1016/j.jfluidstructs.2025.104281","url":null,"abstract":"<div><div>A loosely coupled approach for the prediction of fluid–structure interactions is investigated for a high Reynolds number flow with a shock-wave impinging on a thin flexible panel. The fluid domain is solved using a wall-modeled large eddy simulation (LES), and the resulting time-resolved flowfields are provided as input to a theoretical–computational aeroelastic solver. The computational study mimics the flow and structural conditions of an existing experiment such that the panel displacements can be compared. The approach shows an improvement over an existing theoretical–computational model. For example, predictions of the maximum static deformation, which is a key metric, are shown to be within 10% of the experimental result. Predictions of the time-dependent oscillations of the panel show sensitivity to the coherence length provided to the aeroelastic solver, as noted by Freydin et al. The discrepancy in the magnitude of predicted time-dependent panel oscillations and those observed in the experiment is hypothesized to be due to the lack of instantaneous coupling present in the method, or possibly due to variability in the static pressure of the wind tunnel throughout the run.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"134 ","pages":"Article 104281"},"PeriodicalIF":3.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444766","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

Comprehensive numerical study on the behavior of floating structures under challenging ocean conditions using WCSPH

IF 3.4 2区工程技术

Journal of Fluids and Structures Pub Date : 2025-02-13 DOI: 10.1016/j.jfluidstructs.2025.104273

Shayan Ramezanzadeh , Murat Ozbulut , Mehmet Yildiz

{"title":"Comprehensive numerical study on the behavior of floating structures under challenging ocean conditions using WCSPH","authors":"Shayan Ramezanzadeh , Murat Ozbulut , Mehmet Yildiz","doi":"10.1016/j.jfluidstructs.2025.104273","DOIUrl":"10.1016/j.jfluidstructs.2025.104273","url":null,"abstract":"<div><div>The main objective of this study is to investigate the dynamic motions of floating bodies under different wave conditions. A particle-based numerical method, Smoothed Particle Hydrodynamics (SPH), is used due to its capabilities in modeling violent free surface flows. This work is based on five sub-steps. The first step focuses on ensuring the accuracy of the generated wave characteristics. Then, the heave motion of a point-absorber wave energy converter is examined under regular wave conditions with different power take-off (PTO) damping coefficients. After validating the proposed SPH scheme in a single degree of freedom motion, the roll decay of a rectangular floating body is investigated in the third step by comparing natural frequencies and damping coefficients with available literature data. Subsequently, the roll motion of a fixed floating structure under a wide-range regular wave system is simulated to obtain the corresponding Response Amplitude Operators (RAOs). Finally, the free body motion of a floating body under regular wave excitation is simulated and validated by experimental measurements, considering all rotational and translational motion characteristics. In the light of all simulation results, the proposed SPH numerical scheme can be considered as a useful tool for the design of effective and sustainable offshore structures.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"133 ","pages":"Article 104273"},"PeriodicalIF":3.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394576","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