Effects of Reynolds number on wind effects toward a super-tall building with curved cross-section

Wind resistance is of great importance for the safety and applicability of high-rise buildings, and wind tunnel tests are generally exploited to facilitate associated wind-resistant design. However, owing to the adoption of downscaled models, Reynolds-number (Re) effects on wind tunnel testing results may not be neglected especially for structures with circular or quasi-circular sections. Although great efforts have been made to explore the Re-effects, the range of Re concerned in most studies is too limited to cover that associated with the reality. This article investigates the Re-effects on various wind effects toward a super-tall building which is featured by a spatially varying curved cross-section, based on a comprehensive usage of wind tunnel test and field measurement. The dependence of Strouhal number, pressure, layer force, structural response and equivalent static wind load upon Re from 2.5 x 104 to 3.8 x 107 is analyzed and compared with their counterparts for triangle sections and circular cylinders. Results suggest typical wind effects of the building differ distinctly from those for a circular cylinder. Both the global geometric features of the cross section and its local details (in particular the blunt leading edges) may play a significant role in forming the flow structures around the building and therefore in resulting in corresponding wind effects. Basically, at portions where the cross section varies insignificantly with height, results are much similar to those for a triangle cross-section and are less sensitive to Re; while at portions where the cross section varies significantly with height, some results become dependent greatly upon Re. Overall, the structural responses of this building first increase and then tend to level off with the increase of Re, and wind tunnel testing results basically agree with field measurements when Re exceeds about 1.3 x 105.