Abstract
A pair of conical vortices formed on a flat roof of a low-rise building, when an approaching flow attacks to the building with an oblique angle, randomly exchanges their strength to each other. The phenomenon is called as the 'Switching of conical vortices'.
When a splitter plate was set on the roof to prevent the direct interference between conical vortices on the roof, the switching phenomenon still appeared clearly, while a splitter plate set in the wake of the model eliminated the occurrence of the switching of conical vortices on the roof. These findings considerably justify the idea that the switching of conical vortices on a roof, which were connected to vortices in the wake of the model, can be drawn from the interference between vortices in the wake.
