Journal of Fluids and Structures最新文献

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Progressive flutter prediction using flight data with limited sensors and actuators 基于有限传感器和驱动器的飞行数据的渐进式颤振预测
IF 3.5 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-29 DOI: 10.1016/j.jfluidstructs.2025.104372
John T. Kim
{"title":"Progressive flutter prediction using flight data with limited sensors and actuators","authors":"John T. Kim","doi":"10.1016/j.jfluidstructs.2025.104372","DOIUrl":"10.1016/j.jfluidstructs.2025.104372","url":null,"abstract":"<div><div>In this work, the flutter prediction theory and method originally developed by the author based on the dynamic eigen decomposition technique are modified for applications to flight flutter simulation and testing of airplanes. Towards this end, frequency responses to control surface excitations are processed at subcritical conditions and the dynamic eigenvalues calculated herein are extrapolated to higher dynamic pressures. To obtain enough responses, the flight test is repeated progressively such that the data set is augmented as more responses are added. By using a recursive formula that relates frequency responses at different dynamic pressures it is possible to expand the columns in the transfer function matrix by integer multiples, thus making the measurements and the excitations equal in number. For demonstration of the new methodology, a tapered wing with four flaps is modeled using ten flexible wing modes and four rigid flap modes. Theodorsen’s theory accounting for motion of the control surfaces is employed for unsteady aerodynamics. It is shown that the proposed scheme as applied to the simulated flight data not only results in extremely accurate predictions of flutter but also is procedurally compatible with the present-day practices, e.g., aeroelastic damping extrapolation, providing a viable option for flutter prediction based on flight test data.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"138 ","pages":"Article 104372"},"PeriodicalIF":3.5,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722455","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 unsteady hydrodynamic gust loading on tidal turbine blades 潮汐涡轮叶片非定常流动力阵风载荷建模
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-25 DOI: 10.1016/j.jfluidstructs.2025.104381
Amanda S.M. Smyth , Federico Zilic de Arcos , Anna M. Young
{"title":"Modelling unsteady hydrodynamic gust loading on tidal turbine blades","authors":"Amanda S.M. Smyth ,&nbsp;Federico Zilic de Arcos ,&nbsp;Anna M. Young","doi":"10.1016/j.jfluidstructs.2025.104381","DOIUrl":"10.1016/j.jfluidstructs.2025.104381","url":null,"abstract":"<div><div>This study investigates the blade loads on a model tidal turbine subject to unsteady gust forcing in the form of uniform small-amplitude oscillations in the axial inflow velocity. The validity of industry-standard 2D strip-theory models for calculating unsteady hydrodynamic loading on 3D rotor geometries is evaluated by comparing the 2D results to 3D simulations, both Reynolds-Averaged Navier Stokes (RANS) simulations and 3D inviscid vortex lattice modelling (VLM). The results show that the 2D function captures neither the trends nor the magnitudes of the unsteady turbine loads, which exceed the quasi-steady loads. The inviscid VLM corresponds more closely to unsteady RANS simulations, suggesting that 3D wake effects are a primary driver of the unsteady loads. A key non-dimensional parameter determining the unsteady load magnitudes is identified as the ratio of gust frequency to blade passing frequency. Finally, it is demonstrated that applying conventional tip-loss corrections to 2D unsteady hydrodynamic load models can in some circumstances lead to severely under-predicted blade loads. These outcomes have implications for the evaluation of peak and lifetime loads on tidal devices, and for any rotor application which relies on 2D strip-theory methods for unsteady load evaluation.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104381"},"PeriodicalIF":3.4,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702812","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
Flow-induced vibration of an underwater lazy wave cable in unidirectional current 单向电流作用下水下懒波电缆的流激振动
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-23 DOI: 10.1016/j.jfluidstructs.2025.104385
R. Moideen , V. Venugopal , J.R. Chaplin , A.G.L. Borthwick
{"title":"Flow-induced vibration of an underwater lazy wave cable in unidirectional current","authors":"R. Moideen ,&nbsp;V. Venugopal ,&nbsp;J.R. Chaplin ,&nbsp;A.G.L. Borthwick","doi":"10.1016/j.jfluidstructs.2025.104385","DOIUrl":"10.1016/j.jfluidstructs.2025.104385","url":null,"abstract":"<div><div>This paper describes measurements of the flow-induced vibration of an instrumented model cable in a lazy wave configuration immersed in unidirectional currents in the 2 m deep FloWave Facility at the University of Edinburgh. The cable model, designed to represent a dynamic power cable used in offshore renewable energy structures for electricity transmission, has an external diameter (<em>D</em>) of 31 mm and a mass ratio of 1.22. The current speed was varied from 0.1 to 0.9 m/s and its direction was set at 0, 90, and 180 degrees relative to the initial longitudinal axis of the cable. An underwater Qualisys motion capture system measured the in-line (IL) and cross-flow (CF) displacement components at 36 locations along the length of the submerged cable. Local displacements, response frequencies, and travelling wave modes are determined for reduced velocity <em>U<sub>r</sub></em> ϵ (5.29, 47.69), and Reynolds number Re ϵ (10<sup>3</sup>, 10<sup>4</sup>). It is found that the root mean square (RMS) values of the displacement components exhibited an increasing trend with reduced velocity reaching 0.40<em>D</em> in the in-line direction and 0.45<em>D</em> in the cross-flow direction. For reduced velocity in the range from 5.29 to 10.58, the cable exhibited single frequency vibrations. For <em>U<sub>r</sub></em> &gt; 10.58, the cable experienced broad-banded, multi-frequency responses. Along the cable, certain locations were found to execute distinct circular, elliptical, nearly linear, and figure-of-eight orbits at low <em>U<sub>r</sub></em>. A sudden phase shift was observed along the cable length, related to unsteady vortex-induced vibration (VIV), which effectively prevented lock-in occurring at high <em>U<sub>r</sub></em>.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104385"},"PeriodicalIF":3.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686159","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
Pore-scale numerical analysis of morphological characteristics and their influence on flow behavior in compressed virtual open-cell polyurethane foams 压缩虚拟开孔聚氨酯泡沫的孔隙尺度数值分析及其对流动特性的影响
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-18 DOI: 10.1016/j.jfluidstructs.2025.104351
Alaa-Eddine Ennazii , A. Beaudoin , A. Fatu , P. Doumalin , J. Bouyer , P. Jolly , Y. Henry , E. Laçaj , B. Couderc
{"title":"Pore-scale numerical analysis of morphological characteristics and their influence on flow behavior in compressed virtual open-cell polyurethane foams","authors":"Alaa-Eddine Ennazii ,&nbsp;A. Beaudoin ,&nbsp;A. Fatu ,&nbsp;P. Doumalin ,&nbsp;J. Bouyer ,&nbsp;P. Jolly ,&nbsp;Y. Henry ,&nbsp;E. Laçaj ,&nbsp;B. Couderc","doi":"10.1016/j.jfluidstructs.2025.104351","DOIUrl":"10.1016/j.jfluidstructs.2025.104351","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study presents a numerical investigation integrating morphological characterization and flow response analysis within a porous medium subjected to uniaxial compression. Two modeling approaches are explored: periodic cell structures and Voronoï-based stochastic models. These approaches are analyzed within the framework of XPHD (eX-Poro-Hydro-Dynamic) lubrication, which aims to replace traditional lubricants in turbomachinery guide and support systems with a more efficient and environmentally friendly alternative to minimize energy losses. Identifying optimal materials for XPHD applications presents several challenges due to the continuous interaction between the imbibing fluid and the porous structure under dynamic compression, leading to complex mechanical behaviors. Within this context, the ANR SOFITT project preliminarily identified open-cell polyurethane foams as potential candidates due to their extensive range of physical properties. This study focuses on developing a modeling methodology for open-cell foam structures, aiming to replicate the geometry of polyurethane foams to predict fluid flow behavior under specific XPHD operating conditions. This approach facilitates the evaluation of morphological parameter variations and their impact on key properties necessary for selecting the optimal material. For morphological characterization, tomographic images of polyurethane foam samples subjected to different compression rates are analyzed using the digital volume correlation (DVC) method. The extracted morphological parameters serve as a foundation for generating virtual foams, combining CAD-based modeling with morphological data to create periodic and Voronoï-based structures. For flow modeling, numerical simulations conducted using OpenFOAM are compared with experimental data acquired in a preliminary study. The flow profiles and permeability measurements derived from simulations exhibit strong agreement with experimental observations. Further analysis establishes a correlation between foam internal morphology and fluid flow behavior. Voronoï-based foams demonstrate permeability and tortuosity values closer to those of real foams compared to periodic cell structures, a difference attributed to their respective internal morphologies—random versus periodic. Periodic cell models tend to overestimate permeability due to their uniform ligament configurations, which limit flow disturbances. Additionally, the study examines the deformation mechanisms of virtual foams and their correlation with modeling techniques to assess their suitability for deformation modeling. The Forchheimer coefficient &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; is systematically lower in virtual foams than in real foams, highlighting the reduced inertial effects induced by the simplified numerical structures. The increasing discrepancy in &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104351"},"PeriodicalIF":3.4,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653393","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
Compound-channel-driven shear layer impinging upon streamwise-oriented plates of different solidities 复合通道驱动的剪切层撞击不同凝固程度的顺流取向板
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-18 DOI: 10.1016/j.jfluidstructs.2025.104379
Victor Dupuis , Guillaume Bonduelle , Olivier Eiff
{"title":"Compound-channel-driven shear layer impinging upon streamwise-oriented plates of different solidities","authors":"Victor Dupuis ,&nbsp;Guillaume Bonduelle ,&nbsp;Olivier Eiff","doi":"10.1016/j.jfluidstructs.2025.104379","DOIUrl":"10.1016/j.jfluidstructs.2025.104379","url":null,"abstract":"<div><div>The impingement of a compound open-channel flow upon vertical and streamwise-oriented plates of different solidities located at the edge between main channel and floodplain are investigated experimentally. The plates model finite-length thin hedges along the river bank. The incident flow is characterised by a turbulent shear layer dominated by Kelvin–Helmholtz structures of length <span><math><msub><mrow><mi>L</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>. The solidity of the plates is varied from 17% (i.e. 83% porosity) to 100% (solid plate) in order to represent different vegetation densities, while the plate length is fixed to <span><math><mrow><mn>0</mn><mo>.</mo><mn>56</mn><msub><mrow><mi>L</mi></mrow><mrow><mi>s</mi></mrow></msub></mrow></math></span>. The velocity field at the free-surface is measured by means of Large-Scale Particle Image Velocimetry (LS-PIV) with a field of view of length <span><math><mrow><mn>3</mn><msub><mrow><mi>L</mi></mrow><mrow><mi>s</mi></mrow></msub></mrow></math></span> and covering the channel width. While the solid plate is shown to induce a significant decrease in the incoming turbulent shear stress, the porous plates instead lead to an overshoot in the turbulent shear stress. All plates induce a reduction of the lateral turbulence intensity, while the longitudinal turbulence intensity is never reduced and even strongly overshoots the incident value for the porous plates. The individual Kelvin–Helmholtz structures are altered when passing the plates but are not destroyed. The alteration of the structures increases with the plates’ solidity, but the vortex cores as well as their spatial periodicity are always maintained, and the structures reform to their original state within a relatively short distance downstream of the plates of about <span><math><mrow><mn>1</mn><mo>.</mo><mn>5</mn><msub><mrow><mi>L</mi></mrow><mrow><mi>s</mi></mrow></msub></mrow></math></span>. While for the solid plate the vorticity within the vortex cores decreases by the passage of the plate, in the case of the porous plates the vorticity increases. Vorticity shed from the holes of the porous plates is surmised to be the cause of this increase. The ensemble-averaged Kelvin–Helmholtz structure downstream of each plate reveals that for the least solid plates, the upstream ejection associated with the vortex core is strongly strengthened, which accounts for the observed overshoots in the turbulent stresses. When the plate’s solidity is higher than 67% however, the Kelvin–Helmholtz vortex downstream of the plate has shrunk and weakened, but is accompanied by secondary vortices, generated by the interaction with the plates.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104379"},"PeriodicalIF":3.4,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653394","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
First and second force peaks generated by a surge impact on a wall with and without overtopping 第一次和第二次力峰值是由浪涌冲击在有和没有过顶的壁面上产生的
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-17 DOI: 10.1016/j.jfluidstructs.2025.104380
Mohamed Rozki, Stéphane Abadie, Denis Morichon
{"title":"First and second force peaks generated by a surge impact on a wall with and without overtopping","authors":"Mohamed Rozki,&nbsp;Stéphane Abadie,&nbsp;Denis Morichon","doi":"10.1016/j.jfluidstructs.2025.104380","DOIUrl":"10.1016/j.jfluidstructs.2025.104380","url":null,"abstract":"<div><div>This paper presents a study of dam-break induced surges impact on a wall carried out with a compressible two-phase RANS model. The parameters varied are the reservoir fill height and the wall height. The focus is here on the first and second force peak occurring during the impact and especially their relative magnitude. With an infinitely high wall, the simulations reveal that both, the first and the second peaks increase with the water height in the reservoir and that the second peak is always larger than the first one. The increase of the surge momentum explains the gradual augmentation of both peaks. The second peak being larger than the first is due to the interdependency of both impact phases and the key role of the surge momentum in controlling this dynamics. The non dimensional analysis conducted on these cases, shows that the force peaks increase with the surge Froude number. Nevertheless, it is difficult to relate a specific case to a given Froude number, due to the flow unsteadiness. When the height of the obstacle is finite, the overtopping do not change the first force peak on the front wall face but significantly reduces the magnitude of the second one. Additionally, the maximal horizontal force on the wall, accounting for the force on rear wall face, occur at the beginning (i.e., during the first peak) or at the end of the impact process (i.e., during the second one) depending on the overtopping volume allowed.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104380"},"PeriodicalIF":3.4,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653284","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
Onset instability of inverted flags clamped by a cylinder 由圆柱体夹紧的倒旗的起始不稳定性
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-15 DOI: 10.1016/j.jfluidstructs.2025.104373
Haokui Jiang, Yujia Zhao, Shunxiang Cao
{"title":"Onset instability of inverted flags clamped by a cylinder","authors":"Haokui Jiang,&nbsp;Yujia Zhao,&nbsp;Shunxiang Cao","doi":"10.1016/j.jfluidstructs.2025.104373","DOIUrl":"10.1016/j.jfluidstructs.2025.104373","url":null,"abstract":"<div><div>We numerically investigate the hydrodynamic characteristics and analyze the instability mechanism of a two-dimensional inverted flag clamped by a cylinder. There are two transition routes and a total of six kinds of solutions existing under this configuration for different diameters of cylinders. Specifically, for small cylinders, the undeformed equilibrium UE transitions to deformed-deflected stable SDS through a supercritical pitchfork bifurcation, which is judged by the weakly nonlinear analysis together with the global linear instability analysis. The instability mechanism is the lifting effect of the ‘symmetry-breaking’ mode SM working at the leading edge of the elastic flag. For large cylinders, another unstable ‘vortex-shedding’ mode VM (decoupled with structure mode) causes the disappearance of the UE and SDS solutions, replaced by a small amplitude flapping. The SM and the VM mainly contribute to the growth of perturbations in flag and downstream cylinder regions respectively, which can excite multi-mode oscillating transition analyzed by proper orthogonal decomposition. Moreover, we define two critical diameters <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>V</mi><mi>M</mi></mrow></msub></math></span> dividing the transition from UE to deformed-deflected stable or small amplitude flapping, and both <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>V</mi><mi>M</mi></mrow></msub></math></span> decreases with the increase of Reynolds number. Finally, we prove downstream vortex shedding can induce upward vortex-induced vibration of the flag and further improve the efficiency of energy transfer from the fluid to the structure during small-deflection flapping.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104373"},"PeriodicalIF":3.4,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144623864","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
Effects of the suspended kelp farm on wave propagation: A numerical study 悬浮海带养殖场对波浪传播影响的数值研究
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-11 DOI: 10.1016/j.jfluidstructs.2025.104382
Bo Zhang , Guo-Hai Dong , Chun-Wei Bi
{"title":"Effects of the suspended kelp farm on wave propagation: A numerical study","authors":"Bo Zhang ,&nbsp;Guo-Hai Dong ,&nbsp;Chun-Wei Bi","doi":"10.1016/j.jfluidstructs.2025.104382","DOIUrl":"10.1016/j.jfluidstructs.2025.104382","url":null,"abstract":"<div><div>As an environmentally friendly wave attenuation method, suspended kelp farms show great potential in protecting coastlines and marine engineering structures. To analyze the wave field characteristics around the suspended kelp farm, a three-dimensional numerical wave tank is established using the non-hydrostatic model. The kelp model is developed following the principles of the Euler-Bernoulli law. The effects of wave period, kelp blade density and length, and the distance from the fixed end of the blades to the water surface on the wave field around the suspended kelp farm are studied. The findings indicate that the suspended kelp farm can effectively attenuate wave height and form a trapezoidal area with lower wave heights downstream from it. The wave attenuation effect varies significantly with different wave periods, and when the period increases from 7 s to 10 s, the minimum transmission coefficient on the lee side decreases by 0.36. The increases in kelp density and the length of kelp blades both reduce the average wave height within the sheltered area and cause more noticeable wave reflection and diffraction. However, the size of the sheltered area slightly decreases, especially with higher kelp densities. This study is expected to provide effective guidance for the layout and site selection of suspended kelp farms.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104382"},"PeriodicalIF":3.4,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605551","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 study on the oblique water entry of a vehicle with an asymmetric canard configuration 非对称鸭翼结构飞行器斜入水的实验研究
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-11 DOI: 10.1016/j.jfluidstructs.2025.104383
Wenpeng Li, Cong Wang, Yingjie Wei
{"title":"Experimental study on the oblique water entry of a vehicle with an asymmetric canard configuration","authors":"Wenpeng Li,&nbsp;Cong Wang,&nbsp;Yingjie Wei","doi":"10.1016/j.jfluidstructs.2025.104383","DOIUrl":"10.1016/j.jfluidstructs.2025.104383","url":null,"abstract":"<div><div>The application of flow control techniques is beneficial to improve the hydrodynamic performance of a vehicle during water-entry process. In this paper, the oblique water entry of a vehicle with a single canard wing was experimentally studied. Combined with high-speed photography and an embedded inertial measurement unit (IMU), the cavity evolution and vehicle motion characteristics during oblique water entry at various initial conditions were investigated. The results indicate that the fore-end cavity separated from the surface of the vehicle during oblique water entry. The separated cavity evolved into a jet-pair above the water surface, along with the rear-end cavity. The degree of cavity separation decreased as the impact velocity and entry angle increased, causing the jet-pair to evolve into a single jet. The pinch-off of the fore-end cavity and the rear-end cavity have an instantaneous impact on the vehicle; however, the formation mechanism differ. The hydrodynamic characteristics of the vehicle were evaluated, and the canard-wing configuration effectively corrected the trajectory and attitude deflection of the vehicle during water entry. As the entry angle increased, the offset distance and deflection angle of the vehicle decreased. The findings provide valuable insights for vehicle motion stability during water entry.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104383"},"PeriodicalIF":3.4,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144596367","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
Aero-acoustic-elastic flutter of plates 板的气动声弹性颤振
IF 3.4 2区 工程技术
Journal of Fluids and Structures Pub Date : 2025-07-10 DOI: 10.1016/j.jfluidstructs.2025.104368
Maxim Freydin
{"title":"Aero-acoustic-elastic flutter of plates","authors":"Maxim Freydin","doi":"10.1016/j.jfluidstructs.2025.104368","DOIUrl":"10.1016/j.jfluidstructs.2025.104368","url":null,"abstract":"<div><div>The linear stability of an elastic plate with supersonic freestream flow on one side and a cavity on the other is investigated for the special case when the first acoustic frequency of the cavity is close to the natural frequencies of the plate. To illustrate the effect of aero-acoustic-elastic coupling on flutter onset, a simplified three degrees-of-freedom model is derived including two structural and one dynamic acoustic pressure modes. The model is nondimensionalized to obtain three parameters that describe the acoustic-elastic coupling and one for the aerodynamic stiffness as modeled using Piston Theory aerodynamics. The role of the nondimensional parameters on flutter onset and frequency is investigated. A test case from a recent wind tunnel experiment is analyzed using the full computational model to validate the findings from the illustrative model and quantify the effect of acoustic coupling on flutter onset. A linear stability analysis predicts that the plate used in the experiments is stable at the wind tunnel conditions for cavity depth greater than 60% chordlength. For smaller cavity depth, the plate is expected to flutter as the first and second structural modes coalesce. Wall impedance is included in the analysis to investigate the effect of acoustic damping. Higher-order acoustic-elastic mode crossings are stabilized when acoustic damping is included however the two-mode flutter instability is not affected. These results suggest that the full aero-acoustic-elastic coupling must be considered for accurate prediction of flutter onset and aeroelastic behavior of elastic plates in supersonic flow. Moreover, this phenomenon can be leveraged in wind tunnel experiments to measure post-flutter responses at reduced dynamic pressures by appropriate design of the acoustic cavity.</div></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"137 ","pages":"Article 104368"},"PeriodicalIF":3.4,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589272","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
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