STUDY ON THE APPLICABILITY OF LARGE EDDY SIMULATION METHOD FOR WIND LOAD CHARACTERISTICS OF LOW-RISE BUILDINGS WITH EAVES AND DOUBLE SLOPES UNDER STRONG TYPHOONS

In comparison with the full-scale field measurements and its corresponding wind tunnel tests, this study numerically investigated the aerodynamic loadings on a gable roof of with eaves and double slopes during strong typhoons using Large-eddy simulation method (LESM). The effects of simulation parameters such as typhoon fluctuating wind field artificial synthesis method, near-wall meshing strategy and wall boundary conditions on the wind load characteristics of low-rise buildings with eaves are studied. The reliability of large eddy simulation to predict the wind pressure characteristics of low-rise buildings under strong typhoon is quantitatively analyzed, and the transient characteristics of flow around bluff bodies around low-rise buildings are analyzed by the grounds of the full flow field information of large eddy simulation. The results indicated that CDRFG (Consistent discretizing random flow generation) method could satisfactorily reproduce the highly turbulent typhoon wind field, and the self- turbulence could be simulated by the refined inflow region between the inlet and the place of interest according to the proposed prior grid meshing strategy. The large eddy simulation can obtain the average and fluctuating wind pressure coefficient which is consistent with the field measurement and wind tunnel test, and the reliability of the extreme wind pressure coefficient in the error range of 30% is more than 85%. The flow separation was earlier formed due to the windward roof overhang but resulted in trivial influences on the wind pressure distributions. The local net wind pressure coefficients on the roof overhang were observed to be consistent with the counterparts in the vicinity, which was resulted from the coupling effects between the cylindrical vortex on the upper surface of the roof overhang and local flow separation bubble beneath. The outcomes of this study would improve the confidence of LESM of aerodynamic loadings on low-rise buildings, boost our further understanding of the damage mechanism for wind-induced disasters of low-rise building under typhoon, and provide the valuable reference for the wind-resistant design and enhance the wind-resistant performance of low-rise buildings.