In fractal theory, the fractal dimension has been accepted as a quantitative parameter to measure the complexity of fluctuations and the persistence of wind speeds. Typhoons are extreme wind events that damage structures. In this study, on the basis of wind field measurements, the fractal dimension characteristics of four typhoons in southeastern China are examined. Typhoon wind speeds at different heights and locations are presented. Monofractal dimension analysis was first conducted, and the results revealed that the typhoon wind speeds were persistent, with fractal dimensions smaller than 1.5. For all four typhoons considered, with the onset of landfall, the fractal dimensions approach 1.5, indicating unpredictable trends in the time series. Multifractality is accepted to exist in the typhoon wind speed dataset, and multifractal analysis was also conducted on the basis of the measured typhoon wind speeds. The results show that the fractal parameters calculated by multifractal analysis are generally greater than those calculated via monofractal analysis. This research aims to improve the understanding of the inner dynamic characteristics of typhoon wind speeds. These fractal parameters can provide quantitative references for future typhoon simulations and predictions.
Terrain conditions may significantly affect the near-ground-layer wind speed in coastal areas. In this research, wind tunnel tests and computational fluid dynamics (CFD) were performed to investigate the impact of topographic changes on the local wind field at coastal bridge sites. Considering the geographic information system (GIS) information of an offshore bridge site, a 1:1000 topographic model was constructed to conduct tests in the wind tunnel lab under different wind directions. The influences of terrain conditions on localized wind characteristics such as the wind speed and wind attack angle under different test conditions were obtained. The results show that the wind angle varied between −6° and 6° under different conditions. To more comprehensively show the radius of influence on the local terrain, a CFD simulation was conducted. To verify the results of the wind tunnel tests, the SST k-ω model was compared and selected for simulation in this research. The influence radius of localized wind characteristics was determined by CFD simulation. The results indicate that the original topography showed “reverse amplification” on the leeward side, resulting in complex wake flows. These results may provide a reference for the design of wind-resistant structures such as bridges and offshore wind turbines in coastal areas.
18 December 2025 in International Journal of Structural Stability and Dynamics