THE NUMERICAL SIMULATION OF MOVING DOWNBURSTS AND THEIR INDUCED WIND LOAD ON HIGH-RISE BUILDINGS

The downbursts cause damage to the structures of transmission line towers, wind turbines and so on. It is urgent to study the wind field and the downburst-induced structural wind load. Based on the RANS, computational fluid dynamics (CFD) numerical simulations using the SST k-ω turbulence model were conducted to study the wind field characteristics of downbursts and the wind load on high-rise buildings under the downbursts. A three-dimensional steady-state numerical simulation of a static downburst and the wind load on high-rise buildings under the downburst was carried out. The simulation results were compared with wind tunnel tests. The results show that the established CFD computational model can well simulate the downbursts and the wind load on high-rise buildings. Sliding grid is a technique that can accurately solve multi-motion reference system problems. The numerical simulation of moving downbursts using the sliding grid technology was conducted to study the corresponding downburst wind field and the wind load on high-rise buildings located on the moving path of a jet center. Comparing the radial wind profile of the moving downburst obtained with the measured results and the simulation results by other scholars. It is verified that the wind field characteristics of moving downbursts and the downburst-induced wind load on buildings can be realistically simulated with the aid of the sliding grid technique. A detailed comparison was made between the static and the moving downbursts in terms of wind field characteristics and the wind load on buildings. The results show that the overall movement of the jet port increases the radial wind speed in the moving direction, reduces the wind speed in the negative direction, and increases the pressure coefficient on the building surface. These effects should be considered in the structural design.