Large Eddy Simulation of Flow Around Stay Cable with Upper Rivulet

Abstract:

To understand the relationship between the flow field characteristics and aerodynamics of the cable with the upper rivulet, the flow around and aerodynamic characteristics of a cable model with an upper rivulet were investigated using large eddy simulation (LES) in the subcritical regime. The results show that there exist three distinct flow regimes with the rivulet located at different positions. In the range of θu=0°~50°, the rivulet has little influence on the cable. In the range of θu=50°~70°, with the interferences of the upper rivulet, the upperside shear layer of the cable which is detached from the rivulet can reattach on the cable surface and form a single separation bubble at the upper side of the cable, which induces an asymmetrical pressure distribution on the cable surface. In the range of θu=70°~90°, the upperside shear layer detaches at the rivulet, which causes a lower negative pressure on the upperside surface compared to those of the lowerside of the cable. It is concluded that the appearance and disappearance of the single separation bubble are the underlying reasons for the occurrence of the rainwindinduced vibration (RWIV).

Key words:stay cable; rainwindinduced vibration; large eddy simulation; upper rivulet; separation bubble