Journal of Fluids and Structures最新文献

{"title":"A computational model of red blood cells using an isogeometric formulation with T-splines and a lattice Boltzmann method","authors":"Yusuke Asai ,&nbsp;Shunichi Ishida ,&nbsp;Hironori Takeda ,&nbsp;Gakuto Nakaie ,&nbsp;Takuya Terahara ,&nbsp;Yasutoshi Taniguchi ,&nbsp;Kenji Takizawa ,&nbsp;Yohsuke Imai","doi":"10.1016/j.jfluidstructs.2024.104081","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2024.104081","url":null,"abstract":"<div><p>The red blood cell (RBC) membrane is often modeled by Skalak strain energy and Helfrich bending energy functions, for which high-order representation of the membrane surface is required. We develop a numerical model of RBCs using an isogeometric discretization with T-splines. A variational formulation is applied to compute the external load on the membrane with a direct discretization of second-order parametric derivatives. For fluid–structure interaction, the isogeometric analysis is coupled with the lattice Boltzmann method via the immersed boundary method. An oblate spheroid with a reduced volume of 0.95 and zero spontaneous curvature is used for the reference configuration of RBCs. The surface shear elastic modulus is estimated to be <span><math><mrow><msub><mrow><mi>G</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mn>4</mn><mo>.</mo><mn>0</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></math></span> N/m, and the bending modulus is estimated to be <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>B</mi></mrow></msub><mo>=</mo><mn>4</mn><mo>.</mo><mn>5</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>19</mn></mrow></msup></mrow></math></span> J by numerical tests. We demonstrate that for physiological viscosity ratio, the typical motions of the RBC in shear flow are rolling and complex swinging, but simple swinging or tank-treading appears at very high shear rates. We also show that the computed apparent viscosity of the RBC channel flow is a reasonable agreement with an empirical equation. We finally show that the maximum membrane strain of RBCs for a large channel (twice of the RBC diameter) can be larger than that for a small channel (three-quarters of the RBC diameter). This is caused by a difference in the strain distribution between the slipper and parachute shapes of RBCs in the channel flows.</p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104081"},"PeriodicalIF":3.6,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139700140","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}

{"title":"Aerodynamics on a faithful hindwing model of a migratory dragonfly based on 3D scan data","authors":"Yuma Narita ,&nbsp;Kazuhisa Chiba","doi":"10.1016/j.jfluidstructs.2024.104080","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2024.104080","url":null,"abstract":"<div><p>In this study, we examined the aerodynamics around the hindwing of a faithfully reproduced Pantala Flavescens (globe wanderer) under gliding conditions. The dragonfly wing is corrugated, with numerous veins running through the entire wing. This convexoconcave geometry improves the lift-to-drag ratio under low Reynolds number conditions. However, until now, aerodynamic analyses have only been performed on 2D chordwise cross-sections of the wing and pseudo-3D shapes extending the profiles spanwise. The aerodynamic performance of a 3D geometry that faithfully replicates all wing veins has yet to be investigated. Therefore, we prepared a faithful analytical model by 3D scanning the hindwing of a Pantala Flavescens specimen; as a migratory dragonfly, it is capable of long-duration and long-distance flight. In our simulation results, the V-shaped groove formed by the large wing veins was covered by separation vortices, resulting in a pseudo-smooth wing surface. The role of the differently-sized wing veins is supposedly to inhibit separation. The faithful reproduction of the wings provides a better understanding of the 3D flow structure and directly leads to a precise estimation of the underlying aerodynamic characteristics. Accurate performance must be evaluated by simulating a faithful geometry in low angle of attacks, where aerodynamic efficiency is required for long-distance flight.</p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104080"},"PeriodicalIF":3.6,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139700136","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}

{"title":"Lift enhancement mechanism study of the airfoil with a dielectric elastic membrane skin","authors":"Wei Kang,&nbsp;Shilin Hu,&nbsp;Yanqing Wang","doi":"10.1016/j.jfluidstructs.2024.104083","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2024.104083","url":null,"abstract":"<div><p>Lift enhancement mechanism of an airfoil with the dielectric elastic membrane skin is studied numerically for smart flow control. The flexible membrane is made of dielectric highly elastic polymer material. Such kind of material can deform and oscillate under the prescribed electric potential difference. The dynamic modeling of the dielectric elastic structure is established to describe the electromechanical behaviors. A high-fidelity aero-electromagnetic-structural coupling model is proposed and verified based on CFD/CSD coupling technique. The aerodynamic characteristics of the airfoil with the dielectric elastic membrane skin is analyzed at various angles of attack. The results show that the lift coefficient of the airfoil is 12.33% higher than that of the rigid airfoil at AOA=14°. The effects of coupling oscillation and applied voltages on the aerodynamic performance of the airfoil are emphasized. In the nonlinear coupling, the high-order lock-in frequency plays a significant role in lift enhancement. The lift coefficient is greatly improved when the second-order frequency lock-in occurs and the second-order lock-in frequency is no less than the second-order fundamental frequency of the flow past the rigid airfoil. The corresponding flow pattern is characterized with the formation and maintain of the vortices with similar scale.</p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104083"},"PeriodicalIF":3.6,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139700138","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}

{"title":"The dynamics of cantilevered structures subject to axial flow","authors":"Michael P. Païdoussis","doi":"10.1016/j.jfluidstructs.2024.104075","DOIUrl":"10.1016/j.jfluidstructs.2024.104075","url":null,"abstract":"<div><p><span>The dynamics of slender cantilevered cylinders subjected to internal or external axial flow has been studied extensively from the 1960s onwards. In the early studies, the flow was directed from the clamped end towards the free end of the cantilever. The same is true for cantilevered plates (or “flags”) in axial flow. More recently, however, the dynamics in reverse axial flow, i.e., flow directed from the free towards the clamped end, has received attention, partly as curiosity-driven research, but also because of </span>engineering applications<span><span>. For example, cantilevered pipes aspirating fluid are used in ocean mining, cantilevered cylinders in reverse axial flow may be found as control rods in nuclear reactors, and cantilevered plates in reverse axial flow are a candidate system for </span>energy harvesting.</span></p><p>The present paper provides a summary of the dynamics of these systems in conventional and reverse axial flow and compares their dynamical behaviour. For example, cantilevered cylinders in conventional axial flow are subject to a weak static divergence (buckling) at sufficiently high flow velocities, and to vigorous flutter at higher flow velocities. Cylinders in reverse axial flow, on the other hand, are subject to weak flutter at low flow velocities and to a large amplitude static divergence at higher flows. In the first case the dynamics is sensitive to the shape of the free end, and in the second hardly at all.</p><p>The differences in the dynamical behaviour in reverse flow <em>vis-à-vis</em> conventional flow for pipes and plates, not so neatly reversed as for cylinders, are also discussed, and some general conclusions drawn for all three systems, regarding similarities and differences in the dynamics and sensitivity to free-end shape arising from the direction of fluid flow.</p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104075"},"PeriodicalIF":3.6,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139551902","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}

{"title":"Experimental analysis of trailing edge hydroelastic coupling on a hydrofoil","authors":"P. François ,&nbsp;J.A. Astolfi ,&nbsp;X. Amandolèse","doi":"10.1016/j.jfluidstructs.2024.104078","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2024.104078","url":null,"abstract":"<div><p><span><span><span>This paper explores the conditions for hydroelastic trailing edge vibrations generating tonal noise on a NACA0015 aluminium </span>hydrofoil<span> clamped in a hydrodynamic </span></span>tunnel<span>. Tests were performed for Reynolds numbers </span></span><span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>, ranging from <span><math><mrow><mn>2</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span> up to <span><math><mrow><mn>12</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span><span> and various angles of attack </span><span><math><mi>α</mi></math></span><span>, from 0 up to 10°. A laser vibrometer was used to characterize the hydrofoil vibratory response. Time Resolved Particle Image Velocimetry (TR-PIV) was used to scrutinize the origin of the hydrodynamic excitation mechanism. Hydroelastic trailing edge vibrations of significant amplitude were observed at moderate angles of attack </span><span><math><mrow><mn>4</mn><mo>≤</mo><mi>α</mi><mo>≤</mo><mn>8</mn><mo>.</mo><mn>5</mn></mrow></math></span><span><span>°, for Reynolds number such that the pressure side boundary layer transition was located close to the trailing edge, with a frequency signature allowing a lock-in with the hydrofoil trailing edge structural mode. Two passive solutions were tested to mitigate this hydroelastic flow-induced vibration: a truncated hydrofoil and a triggered one. The truncated configuration slightly impacts the vibration while triggering the pressure side boundary layer transition ahead of the trailing edge eliminates the trailing edge vibrations with negligible impact on the hydrofoil </span>hydrodynamics performances.</span></p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104078"},"PeriodicalIF":3.6,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139549631","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}

{"title":"Numerical investigation of liquid sloshing in 2D flexible tanks subjected to complex external loading","authors":"Kim Q.N. Kha ,&nbsp;Mustapha Benaouicha ,&nbsp;Sylvain Guillou ,&nbsp;Abdelghani Seghir","doi":"10.1016/j.jfluidstructs.2024.104077","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2024.104077","url":null,"abstract":"<div><p><span>Due to the complexity of fluid–structure interactions (FSI), the majority of studies in the literature dealing with the sloshing problem are restricted to rigid tanks. This paper is devoted to a numerical investigation of the liquid sloshing behavior in a flexible tank subjected to external loading. A numerical methodology is proposed, taking into account the FSI problem by coupling two open-source codes: OpenFOAM for the fluid and FEniCS for the solid, using the preCICE library, a free library for fluid–structure interaction. The Arbitrary Lagrangian–Eulerian formulation is used for the two-phase flow system to solve the Navier–Stokes equations in the fluid domain using the finite volume method. Simultaneously, the linear-elastic equation of the structure is solved using the finite element method. An implicit coupling scheme is considered at the fluid–structure interface. The numerical methodology is validated by the results given in literature for </span>harmonic excitation<span><span><span> at different frequencies. Subsequently, an analysis of complex external loading, such as Gabor wavelets and </span>earthquake ground motion, is conducted to highlight the significant impact of the wall flexibility on sloshing, as well as the influence of </span>hydrodynamic forces on the structure’s deformation. The proposed coupling methodology is robust and effective, it can be applied to all types of liquids and materials. A dataset of one of the studied cases is given as a supplement to the paper (Kha et al., 2024).</span></p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104077"},"PeriodicalIF":3.6,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139549630","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}

{"title":"Numerical modelling of a vertical cylinder with dynamic response in steep and breaking waves using smoothed particle hydrodynamics","authors":"Yong Yang ,&nbsp;Aaron English ,&nbsp;Benedict D. Rogers ,&nbsp;Peter K. Stansby ,&nbsp;Dimitris Stagonas ,&nbsp;Eugeny Buldakov ,&nbsp;Samuel Draycott","doi":"10.1016/j.jfluidstructs.2023.104049","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2023.104049","url":null,"abstract":"<div><p>Highly nonlinear near-breaking and spilling breaking wave groups are common extreme events in the ocean. Accurate force prediction on offshore and ocean structures in these extreme wave conditions based on numerical approaches remains a problem of great practical importance. Most previous numerical studies have concentrated on non-breaking wave forces on rigid structures. Taking advantage of the smoothed particle hydrodynamics (SPH) method, this paper addresses this problem and presents the development and validation of a numerical model for highly nonlinear hydrodynamics of near-breaking and spilling breaking waves interacting with a vertical cylindrical structure using the SPH-based DualSPHysics solver. Open boundaries are applied for the generation of extreme wave conditions. The free-surface elevation and flow kinematics pre-computed within another numerical model are used as boundary conditions at the inlet of a smaller 3-D SPH-based numerical model to replicate the near-breaking and spilling breaking waves generated in a physical wave flume. A damping zone used for wave absorption is arranged at the end of the domain before the outlet. Numerical results are validated against experimental measurements of surface elevation and horizontal force on the vertical cylinder, demonstrating an agreement. After validation using a fixed model for the cylinder, a dynamic model is used to study the response to extreme wave events. Numerical results have also shown that the spilling breaking wave forces are significantly larger compared with near-breaking wave forces, and the secondary load cycle phenomenon becomes larger with dynamic response included in the present study.</p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104049"},"PeriodicalIF":3.6,"publicationDate":"2024-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0889974623002177/pdfft?md5=4874304b73171f3bb182b5e87a9f296a&pid=1-s2.0-S0889974623002177-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139503932","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}

{"title":"Modeling vortex-induced vibrations of branched structures by coupling a 3D-corotational frame finite element formulation with wake-oscillators","authors":"Alexandre Villié ,&nbsp;Mauricio C. Vanzulli ,&nbsp;Jorge M. Pérez Zerpa ,&nbsp;Jérôme Vétel ,&nbsp;Stéphane Etienne ,&nbsp;Frédérick P. Gosselin","doi":"10.1016/j.jfluidstructs.2024.104074","DOIUrl":"10.1016/j.jfluidstructs.2024.104074","url":null,"abstract":"<div><p><span>Branched structures are present in a diverse set of problems, from modeling branch pipe connections to simulating tree dynamics. Soft corals like the Bipinnate sea plume, have a branched geometry and are soft enough to bend under the waves. Due to their circular cross section<span><span>, a vortex street forms in the coral’s wake inducing vibrations of its branches. Despite extensive studies on </span>VIV in straight geometries, the three-dimensional (3D) dynamics of flexible branched structures remains uninvestigated. In this numerical and experimental study, we develop a novel formulation for the accurate computation of in-line and cross-flow VIV of frame structures undergoing </span></span>large deformation<span><span>. The finite element approach is used to model arbitrarily complex geometries of branched frame structures. Our formulation allows to model complex geometries with forks or sharp angles. The consistent 3D corotational formulation for frame elements computes the internal, inertial and hydrodynamic forces. A wake-oscillator approach models the near wake dynamics with fluctuating fluid forces on the structure in the in-line and cross-flow directions. The drag and lift coefficients follow distributed </span>Van der Pol oscillators<span>. Moreover, we implement the numerical resolution procedure in the open-source library ONSAS. The present formulation and numerical resolution procedure is validated by solving three examples, including comparisons with an analytical solution, a wake-oscillator, and experimental data from the literature. We also conduct experiments of a flexible and elastic cylinder<span> clamped inside a water tunnel<span><span> under a constant uniform flow. Amplitudes and power spectral density of the tip transverse displacements are compared with the model prediction. Finally, the proposed formulation is applied on a cylinder with two branches. The simulations demonstrate a multi-frequency response with higher amplitudes of displacements when additional branches are incorporated onto the cylinder, emphasizing the significance of considering VIV in nature and </span>engineering applications for such geometries.</span></span></span></span></p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104074"},"PeriodicalIF":3.6,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139496743","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}

{"title":"Pore-scale numerical analysis of fluid flows in compressed polyurethane foams with a workflow of open-cell foams modeling","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.2023.104065","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2023.104065","url":null,"abstract":"<div><p><span>eX-Poro-HydroDynamic (XPHD) lubrication presents a different scientific approach to dealing with tribological problems. It is an innovative inter- and multidisciplinary research topic which offers a promising sliding solution for various applications, such as </span>thrust bearings<span><span><span>, various guide components and in terms of load capacity and damping. XPHD lubrication is a lubrication mechanism of biomimetic inspiration which features an additional parameter to the system “the porous media”. It consists of self-sustained fluid films generated within compressible </span>porous layers<span> imbibed with liquids in replacement for using the fluid film only as in the classic lubrication system<span>. Soft and porous structures<span> imbibed with liquids generate a high load support under compression. The load support is generated through the resistance to flow inside the porous material. During compression, the resistance to flow and load support increases the greater the compression rate. The main objective of this work is then to understand the behavior of the fluid flow inside the porous structures when subjected to axial compression<span> stress. In the scientific literature, the works studying the flow in compressible materials are essentially experimental because of their very complex geometrical shape, the CFD (Computational Fluid Dynamics) simulations offer an economical solution to study the performance of this new concept of lubrication. To create the geometry, the morphological structures of foam samples are reconstructed at different levels of compression rates from 3D (Three Dimensional) X-ray microtomography. This is achieved by using the commercial software Avizo that allows to process 3D images and create 3D meshes suitable for numerical simulations. The numerical simulations of flows will be performed with the solver IcoFoam of the toolbox OpenFOAM for incompressible </span></span></span></span></span>laminar flows<span>, making it possible to study the pressure drop in these porous structures. The performed simulations were made with a polyurethane foam of 96% porosity using five compression rates for creating the different structures. The analysis of the numerical simulations shows the impact of the polyurethane foam compression on different key parameters such as the decrease in the permeability as function of the compression rate, the anisotropy of the flow within the compressible structure and the actual increase in the tortuosity generated by the compression of the foam and the variation of the porosity.</span></span></p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104065"},"PeriodicalIF":3.6,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139487931","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}

{"title":"ADV measurements of blockage flow effects near a model jacket in waves and current","authors":"A.J. Archer ,&nbsp;H.A. Wolgamot ,&nbsp;J. Orszaghova ,&nbsp;S. Dai ,&nbsp;P.H. Taylor","doi":"10.1016/j.jfluidstructs.2024.104076","DOIUrl":"https://doi.org/10.1016/j.jfluidstructs.2024.104076","url":null,"abstract":"<div><p>Design standards for drag loading on offshore jacket structures do not presently account for the reduction in forces arising from flow blockage effects in the event of combined waves and current. This force reduction is believed to originate in reduced mean flow velocity through the jacket, but this has never been directly measured. To address this, we conducted physical-model tests which measured the flow adjacent to a jacket structure in combined waves and in-line currents using acoustic Doppler velocimeters. Results confirm a dramatic reduction in the mean flow velocity up-wave and down-wave of a model jacket in waves and current, far greater than the flow reduction observed in current alone. These results unambiguously confirm the significant additional blockage (and hence reduction in structural loads) not captured in current offshore design standards.</p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"125 ","pages":"Article 104076"},"PeriodicalIF":3.6,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0889974624000112/pdfft?md5=ecd585045ca48e105c95c7e506559435&pid=1-s2.0-S0889974624000112-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139487930","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}