Numerical study of the wind loads on a cooling tower by a stationary tornado-like vortex through LES

A tornado simulator is built and large eddy simulations are carried out to model the swirling flow fields in a tornado-like vortex and the tornado-induced wind loads on a cooling tower. When the cooling tower is close to the tornado core, the mean and fluctuating loads exerted by the tornado tend to be much larger than those applied by a straight-line wind. However, when the cooling tower is sufficiently far from the center of the tornado, r>3.0rc, the aerodynamic force coefficients show almost the same value as those induced by the straight-line wind. In the tornado core, the forces show the maximum fluctuations. To explain these large force fluctuations, spectrum analyses are carried out and two peaks are identified. These two peaks are found to be the result of two factors, i.e., the sub-vortices in the tornado and the vortex shedding in the wake of the cooling tower. This is the most important finding in this study, and it clarifies the dynamic response of a cooling tower exposed to a tornado.