Validation of a novel transition curve for simulating wind fields in complex terrain using field measurements

Computational Fluid Dynamics (CFD) numerical simulation is a cost-effective and reproducible technique that has become a pivotal tool for researching wind characteristics in complex terrains, which is a critical area of investigation for wind resistance in large-span bridges. To ensure reliable those CFD analysis, it is crucial to rely on effective transitional curve. In this study, a novel transition curve based on the Bernstein basis function is proposed, which exhibits superior transition capabilities compared to existing transition curves applied in ideal terrains under comprehensive indices. Subsequently, this curve was applied to numerically simulate the wind field in a gorge terrain bridge site. The simulated spatial mean wind field was compared with three years of measurement data along a long-span bridge. The findings indicate that in the absence of transitional curves in terrain models of varying scales, the simulated wind speed distribution along the bridge can differ significantly from the actual measurements. However, the addition of various transitional curves yields superior results, with the recommended transitional section performing the best, with the relative error in wind speed for the dominant wind direction of less than 10%. Furthermore, the recommended transitional curve demonstrates strong applicability to terrain models of different sizes.