Characteristics of signature turbulence on long span flat roofs

This paper presents the definition of signature turbulence and some representations, especially introducing one typical kind of building generated turbulence, conical vortices on flat roofs. The characteristics of conical vortices are investigated by wind tunnel test, some character parameters are identified through contour maps of roof surface wind pressure coefficient, including the position of the maximum mean suction for the axis of the conical vortex and the position of the maximum r. m. s. pressure coefficient for the width of the conical vortex. The movement of conical vortex is also investigated by studying the changes of wind pressure on some crosswind and longitudinal section. Finally the vortices regions marked are useful for establishing a reasonable gust wind model or a general power spectra of wind pressures.