The wind flow around twin-box decks is particularly complex due to the very important role played by the slot distance between girders and the presence of the downwind box that is immersed in the wake of the upwind box. Detailed experimental studies on the three-dimensional flow features of this deck typology are certainly challenging, and CFD simulations have not tackled this problem so far. The goal of this 3D LES piece of research is to shed some light on the complex flow features around twin-box decks, particularly when the deck geometry is fully three-dimensional due to the presence of the transversal beams linking together the deck girders. Integral parameters, mean and instantaneous flow structures and spanwise correlations are studied for a segment of the Stonecutters Bridge. It has been found that the presence of the transversal beam plays a key role in the flow correlation loss, identifying, for instance, the out-of-phase shedding of vortices at different sides of the transversal beam. The numerical results agree well with experimental data in the literature, and offer a richer and more comprehensive explanation for the identified aerodynamic responses.

由于大梁之间的缝隙距离以及浸入迎风箱后部的顺风箱的存在，双箱甲板周围的风特别复杂。对这种甲板类型的三维流动特征进行详细的实验研究无疑是具有挑战性的，到目前为止，CFD模拟尚未解决该问题。这项3D LES研究的目标是为双箱式甲板周围的复杂流动特征提供一些启发，尤其是当由于横梁将甲板大梁连接在一起而使甲板几何形状完全为三维时。研究了昂船洲大桥一段的整体参数，均值和瞬时流量结构以及跨度相关性。已经发现，横向束的存在在流动相关性损失中起关键作用，例如，确定横向束的不同侧上的涡流的异相脱落。数值结果与文献中的实验数据非常吻合，并为确定的空气动力响应提供了更丰富，更全面的解释。