The spatial and temporal characteristics of the pressure fields on the roof and wall edges of a low-rise building with a 4: 12-pitched roof have been investigated by using a data-base, which was constructed at BLWTL, The University of Western Ontario. This paper presents the results on the characteristics of pressure distributions. Special attentions are paid to the spatial extent and the duration of severe suctions. Detailed analyses of the data are made for the wind direction which gives the highest suctions near the leading edge for particular surfaces of the building. The variation of pressure distribution with time is described. The results indicate that the area of severe suctions is relatively small, smaller than that of a plywood commonly used in the North America, and that the duration is rather short, such as 0.2 to 0.3 sec. in full scale. Furthermore, it is found that the large peak suctions occur with similar pressure distribution patterns.

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This paper deals with the evaluation on aerodynamic characteristics of a square cylinder oscillating in the across-wind direction. Two-dimensional flow calculation was executed by using k-ε with a modified production eddy viscosity model. Calculated results were compared with experimental ones mainly obtained in this study. Firstly two patterns of aerodynamic response with different mass-damping parameters were predicted. Secondly unsteady lift acting on a oscillating cylinder were predicted. Although a slight difference was observed between predicted unsteady lift coefficients and experimental ones, accuracy in predicting aerodynamic response was far better than that of unsteady lift coefficients.

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Aerodynamic behavior of forkball and fastball are studied in a stand point of fluid dynamic research. The fastball rotates in backspin and aerodynamic lift force acts on it is toward upward by Magnus effects. This lift force is the same magnitude with gravity force for good fastball. As a result, the fastball trajectory is nearly straight toward homebase after detaching pitcher's finger. The other hand, good forkball spins around vertical axis. In this case, less lift force and only the gravity force act on the ball. The flight trajectory of the forkball results in vertically sinking line only by the gravity force and laterally sliding one by side spinning effects in its final stage near the homebase.

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