Advances in wind engineering., Год журнала: 2024, Номер 1(2), С. 100027 - 100027
Опубликована: Дек. 1, 2024
Язык: Английский
Physics of Fluids, Год журнала: 2024, Номер 36(3)
Опубликована: Март 1, 2024
The triple-box girder is finding broader applications in super long-span bridges for its excellent performance of flutter stability and traffic adaptability. In the present study, a bridge model with three separated boxes experimentally investigated detail via wind tunnel tests. consideration web modifications accessory structures, multi-point surface-pressure measurement smoke-wire flow visualization are applied to investigate aerostatic characteristics structures. “dual-frequency” phenomenon found explained bare curved webs. For linear webs, global field dominated by separated-shear-layer instability. upstream gap instability while downstream double-shear-layer exhibits obvious intermittent characteristics. addition, non-Gaussian characteristic analysis surface pressures introduced improved engineering practice. distinguishing principle based on skewness kurtosis has high adaptability both completed bridge. semi-linear webs show better drag reduction. Combinations structures also studied. results that during construction process, prioritizing installation highway barriers can optimize bridges. study embraces booming era enriches studies aerostatics.
Язык: Английский
Процитировано
16
Physics of Fluids, Год журнала: 2024, Номер 36(3)
Опубликована: Март 1, 2024
To fully use the land resource in urban regions of metropolises, high-rise buildings large aspect ratio maybe preferred for new constructions. systematically investigate across-wind responses these quite slender structures, boundary layer flow high turbulence intensity was simulated wind tunnel, and aeroelastic tests realized by pivot model setup were carried out square cross section towers various heights resulting ratios (λ = 12, 16, 20). No appreciable behaviors have been observed λ 12 tower even a very low damping (0.57%). This is line with many previous studies tall-square an not higher than 10, likely due to terrain, mitigating occurrence possible behaviors. In contrast, 16 (especially) 20 exhibit strong oscillations known as galloping, evidenced monotonic increase amplitude–velocity curve clear characteristics simple-harmonic oscillations. Moreover, it that certain range ratios, initiated at same speed close vortex-resonance speed. The interaction mechanism between vortex induced vibration galloping thus supposed responsible this observation (even flow). Finally, peak provided well, serving useful reference future design similar towers.
Язык: Английский
Процитировано
7
Physics of Fluids, Год журнала: 2024, Номер 36(8)
Опубликована: Авг. 1, 2024
Due to the existence of upstream and downstream gap, flow dynamics around a separated triple-box girder becomes quite complex. This work explores girder, i.e., multiple separation–reattachment effect, shear layers' impingement–rebound separated- double-shear-layer instability, etc. Three angles attack (AOAs), 0°, +5°, −5°, were considered for investigating vortex classical Reynolds number (Re) was set at 1.05 ×104. The time-averaged instantaneous fields as well distribution fluctuating magnitude are discussed. results show that, under 0°AOA, gap (flow in gap) is characterized by layer impingement while intermittent vortex-shedding appears gap. Time–frequency analysis reveal that spectral intermittency caused oscillations lower layer. different analyzed detail proper orthogonal decomposition analysis. Under +5°AOA, interactions layers both gaps weak periodicity, instability dominates whole field. −5°AOA, flows. periodical shedding vortices observed simultaneously with varied dominant frequencies. complex impacts effect essence “multi-frequency” phenomenon also revealed.
Язык: Английский
Процитировано
3
Physics of Fluids, Год журнала: 2024, Номер 36(5)
Опубликована: Май 1, 2024
The aerodynamic performance of the flow around a cylinder with two free ends, which is also referred to as finite-length cylinder, continues be subject rigorous academic inquiry. However, limited research has been conducted on cylinders rough surfaces. To evaluate impact relative roughness we performed numerical simulations model an aspect ratio 1.5 various values. These covered range Reynolds numbers from 3.9 × 103 4.8 105. results indicated that both and number could affect characteristics by altering pattern cylinder. As increased, four spiral eddies behind gradually lost their symmetry in axial direction eventually transformed into pair recirculating eddies. Moreover, when was constant at 2.0 104, increase surface triggered same phenomenon. Additionally, mechanism affected coefficient current revealed. This influence mainly attributed pressure backside
Язык: Английский
Процитировано
2
Physics of Fluids, Год журнала: 2024, Номер 36(5)
Опубликована: Май 1, 2024
The flapping dynamics of a flexible membrane (FM) and its effect on the flow fields over pressure fluctuations forward-facing step (FFS) have been investigated experimentally. two-dimensional FM with 40 mm in length 0.15 thickness was vertically attached to leading edge FFS height. deformation recorded by high-speed camera. Velocity data vertical central plane surface were measured planar particle image velocimetry sensors, respectively. results demonstrate that as dimensionless bending rigidity (γ) decreases, displayed two distinct modes, i.e., mode mode. In mode, bent is similar curved barrier, which elevates shear layer delays reattachment separation flow. amplitude increases decrease γ, turn effects scale flapping-induced vortices (FIVs). proper orthogonal decomposition analysis, reveal transition dominant structure from large-scale FIVs reducing γ. significantly affect distribution FFS, range where coherent contribution dominates expands decreasing
Язык: Английский
Процитировано
2
Physics of Fluids, Год журнала: 2024, Номер 36(7)
Опубликована: Июль 1, 2024
In structural health monitoring (SHM), wind field sometimes suffers from data loss owing to device failure, which inevitably creates barriers subsequent analysis and mining. To this end, a novel strategy for reconstructing missing based on machine learning (ML) utilizing limited pressure measurements is proposed in paper. Several ML algorithms, including decision tree, random forest, gradient boosting regression support vector regression, Gaussian process backpropagation neural network, are employed characterize potential relationships between information (including time series statistical parameters of pressures) (e.g., direction speed). Moreover, the effect input type variables as well number location transducers providing data) reconstruction performance efficiency investigated. Field measured records an SHM system 600-m-high supertall building during typhoons utilized validate feasibility robustness strategy. The results show that presented can effectively reconstruct skyscraper typhoons. Compared with pressures, selecting pressures improve models. Choosing appropriate using multiple variables, adopting larger transducers, closer anemometer) beneficial enhancing
Язык: Английский
Процитировано
2
Nonlinear Dynamics, Год журнала: 2024, Номер 112(18), С. 15741 - 15756
Опубликована: Июнь 19, 2024
Язык: Английский
Процитировано
1
Physics of Fluids, Год журнала: 2024, Номер 36(8)
Опубликована: Авг. 1, 2024
This study utilized wind tunnel experiments and large eddy simulations to profoundly investigate the aerodynamic characteristics flow patterns surrounding flat girders with different aspect ratios (B/D = 2, 4, 7, 10, where B D are length height of girder, respectively), which covers most engineering applications for typical long-span bridges. The test range angle attack (AOA) is [−12°, 12°]. Reynolds number Re, based on freestream velocity U∞ D, was approximately 70,900. results revealed that, separation point girder gradually moved downstream, an obvious bubble generated at leading fairing increase in AOA, especially cases B/D 10. performance case 2 differed substantially from other cases, experiencing largest mean drag smallest fluctuation pressure −10° ≤ AOA 10°, attributed patterns. Specifically, leading-edge vortex shedding occurred whereas impinging (AOA 0° 4°) a combination trailing-edge 8°) were identified 4 respectively, dominated determined Additionally, effects showed relatively minor when |AOA| < 4° as compared > 4°. For thickness upper surface boundary layer turbulence intensity enhanced resulting higher multiple dominant peaks lift spectrum. However, this effect significantly attenuated 10 due dissipation effect. may offer guidelines relevant applications.
Язык: Английский
Процитировано
1
Deleted Journal, Год журнала: 2024, Номер 1(3), С. 309 - 328
Опубликована: Янв. 1, 2024
<p>Bladeless wind turbines are attracting attention as energy harvesters due to several conveniences like the ease of construction and suitability for operating under small speed. As a grouped generation system, it is likely simplest configuration compared farms. However, characterization tandem requires deep understanding effects produced by interaction two. Therefore, this work considered set two conical cylinders representing harvesters, which lie on bottom tunnel were subjected resonance conditions. The focused evaluating separation distance between three distances: $\ell$ = 0.25<italic>h</italic>, 0.5<italic>h,</italic> 0.75<italic>h</italic>, where <italic>h</italic> cylinder's total height. Oscillation vortex shedding was numerically predicted. analysis centered fluid-structure in pairs generators wind-induced resonance, how them affects their oscillation. Experimental data cylinder vibration measured served validate numerical results. results showed strong wake second placed downstream from first one 0.25<italic>h</italic>. In contrast, minimum observed ℓ 0.5<italic>h</italic> 0.75<italic>h</italic>.</p>
Язык: Английский
Процитировано
1
Advances in wind engineering., Год журнала: 2024, Номер 1(2), С. 100027 - 100027
Опубликована: Дек. 1, 2024
Язык: Английский
Процитировано
0