Nan-You Lu

The Shenao site on Taiwan’s northeastern coast, formerly occupied by a coal-fired power plant, is being considered for renewable energy development. This study presents the first systematic wind energy assessment of a repurposed power plant site in Taiwan, integrating field measurements, long-term wind data extrapolation, and computational fluid dynamics (CFD) simulations. Nearly two years of Doppler LiDAR observations were collected to characterize wind speed distribution, shear exponent, turbulence intensity, and flow inclination. To extend this record, the Measure-Correlate-Predict (MCP) method with reanalysis datasets was applied to estimate long-term wind conditions. In parallel, high-resolution CFD simulations incorporating LiDAR data and local terrain were conducted to map wind fields, evaluate wind power density, and support turbine micrositing. Results indicate moderate wind potential, with a CFD-estimated wind power density of ~200 W m ⁻² . A preliminary layout with three Vestas V80 turbines yields an average of ~1,392 full-load hours per year and a capacity factor (CF) of 15.9%, comparable to typical onshore wind farms. These findings demonstrate the feasibility of repurposing fossil-fuel sites for wind energy and establish a transferable framework for assessing wind resources in complex terrain.

This study establishes a comprehensive framework to investigate subsurface delamination in XM‐19 stainless steel during three‐roll planetary rolling, overcoming the limitation of conventional failure theories, which cannot detect internal cracking. Experimental efforts include metallurgical analysis, high‐temperature tensile testing, and melting point measurements. The zero‐ductility temperature (ZDT) of XM‐19 is 1,290 °C, and its melting range (1,311.1–1,398.8 °C) validates results from thermophysical evaluation. The estimated thermal conductivity is incorporated into finite element simulations to model deformation and thermal evolution during rolling. Benchmark simulations, validated by experiments, reveal a hot core region reaching ZDT ≈9.95 mm below surface, consistent with observed cracks. Circumferential flow velocities of 250–300 mm s ⁻¹ at the roll‐bar interface contribute to delamination initiation. A parametric study shows that slower revolution and roll rotational speeds reduce the hot core volume ( V _hc ) significantly—with an 85% speed reducing V _hc to 0.05% of that in the control case. Conversely, reducing the bar size decreases roll‐bar contact area, intensifies heat accumulation, and may increase delamination risk. These findings provide insights into thermally driven failure mechanisms and offer guidance for optimizing planetary rolling parameters to minimize internal cracking and improve product integrity.

This study investigates transient wave propagation behavior and introduces an innovative approach for damping ratio identification in multi-span bridge plates. The transient response, incorporating damping effects, is efficiently predicted using the modal superposition method. By integrating theoretical analysis with experimental data, a refined iterative method is introduced to identify the damping ratio for each resonant frequency by extracting frequency spectrum peaks from experimental data. This simple yet effective methodology enhances the accuracy of transient response predictions. Experimental measurements of transient strain and impact force histories are obtained using polyvinylidene fluoride (PVDF) sensors. Results validate that transient strain and displacement predictions remain consistent across both time and frequency domains, especially considering damping effects. In addition, variations in identified damping ratios across different impact and sensor configurations reflect the energy dissipation when impact waves traverse simply supported boundaries, highlighting the need to combine modal damping estimates from multiple testing configurations. Compared to numerical simulations, the proposed method achieves high accuracy while significantly reducing computational effort. With its flexibility and precision, the proposed approach has the potential to be extended to complex structural systems and diverse material applications, enhancing real-time structural health monitoring across various engineering fields.

Two-way fluid–structure interaction (FSI) simulation of wind turbines has gained significant attention in recent years due to the growth of offshore wind energy development. Strong coupling procedures in these simulations predict realistic behavior with higher accuracy but result in increased computational costs and potential numerical instabilities. This paper proposes a mixed weak and strong coupling approach for the FSI simulation of a 5 MW wind turbine. The deformation of the turbine blade is calculated using a weak coupling approach, ensuring blade deflection meets a convergence criterion before rotating to the next azimuthal position. Fluid and solid solvers are partitioned, utilizing the commercial software packages STAR-CCM+ and Abaqus, respectively. Flexible and rigid blade cases are modeled, and the calculated loads, power, and blade tip displacement for the rotor at a constant rotating speed are compared. The proposed model is validated, showing good agreement with the existing literature and results comparable to those from another validated wind turbine simulator. The effect of rotor–tower interaction is evident in the results. Based on our calculations, the power production of flexible blades is evaluated to be 9.6% lower than that of rigid blades.

Thunderstorm downbursts have been reported to cause damage or failure to wind turbine arrays. We extend a large-eddy simulation model used in previous work to generate downburst-related inflow fields with a view toward defining correlated wind fields that all turbines in an array would experience together during a downburst. We are also interested in establishing what role contrasting atmospheric stability conditions can play on the structural demands on the turbines. This interest is because the evening transition period, when thunderstorms are most common, is also when there is generally acknowledged time-varying stability in the atmospheric boundary layer. Our results reveal that the structure of a downburst’s ring vortices and dissipation of its outflow play important roles in the separate inflow fields for turbines located at different parts of the array; these effects vary with stability. Interacting with the ambient winds, the outflow of a downburst is found to have greater impacts in an “average” sense on structural loads for turbines farther from the touchdown center in the stable cases. Worst-case analyses show that the largest extreme loads, although somewhat dependent on the specific structural load variable considered, depend on the location of the turbine and on the prevailing atmospheric stability. The results of our calculations show the highest simulated foreaft tower bending moment to be 85.4 MN-m, which occurs at a unit sited in the array farther from touchdown center of the downburst initiated in a stable boundary layer.

Severe winds produced by thunderstorm downbursts pose a serious risk to the structural integrity of wind turbines. However, guidelines for wind turbine design (such as the International Electrotechnical Commission Standard, IEC 61400-1) do not describe the key physical characteristics of such events realistically. In this study, a large-eddy simulation model is employed to generate several idealized downburst events during contrasting atmospheric stability conditions that range from convective through neutral to stable. Wind and turbulence fields generated from this dataset are then used as inflow for a 5-MW land-based wind turbine model; associated turbine loads are estimated and compared for the different inflow conditions. We first discuss time-varying characteristics of the turbine-scale flow fields during the downbursts; next, we investigate the relationship between the velocity time series and turbine loads as well as the influence and effectiveness of turbine control systems (for blade pitch and nacelle yaw). Finally, a statistical analysis is conducted to assess the distinct influences of the contrasting stability regimes on extreme and fatigue loads on the wind turbine.