9503620 Wu This research consist of theoretical and experimental studies to determine the mechanism of natural hazards due to extreme winds and ocean currents and to develop methods for significant reduction of such hazards inflicting on tall buildings, offshore structures and highway infrastructures. The main goals of this program are: - to achieve significant reduction of vortex-induced or side sway of the structures transversal to the flow stream; - to invent vortex-generating control devices for executing the required active or passive control functions; and - to find effective methods for reducing streamwise drag. Both active and passive modes of control will be considered so as to cover structures of various scales and diversified geometric configurations. Empirical approach will be followed to pursue a heuristic yet creative development of the vortex-generating devices for executing the required control functions.