Laboratory investigations of tornado-like vortices are reviewed. Various types of the laboratory models using air are introduced.The abilities and the limitations of the laboratory investigations are discussed on various specific problems with the emphasis being placed on the vortex boundary layer and the interaction between the vortices and the ground surface or the buildings and the structures.A number of problems left unsolved in the present laboratory works art summarized.in the future investigations, a model jr which the inflow profiles of the mean velocity (both radial and tangential) and the turbulence level are adjustable is suggested.
A cable-stayed bridge, which is a flexible structure and easy to oscillate due to wind action, requires an aerodynamic investigation for each design.Some examples of the aerodynamic test results of the cable-stayed bridges in United States of America are presented here.Many of the designed bridge decks meet vortex-excited oscillations.In some cases the countermeasures to prevent the oscillations are introduced, in other cases the checks are done whether the amplitude of oscillation is allowable.The design damping and the tolerance level to oscillation are the important factors to assess the safety and the usability of a bridge under vortex-excited oscillation.The American cablestayed bridges have high design dampings to estimate the behavior of a proto type.
As part of a long range study to develop commercial sailing ships, wind tunnel tests and tank tests were carried out using scale models, and full scale measurements were made using the experinmntal ship, PAWN.To confirm the results of these studies, a l6000WT sail-assistedtanker, SNIN A/TOKO WARP, has been built and subjected to various sea trials. This paper presents the results of the wind tunnel tests conducted to investigate the aerodynamic characteristics of sails and hulls and the results obtained from the sea trials and the actual voyages of the SHIN AITOKU MAU.The tank test results are summarised placing emphasis on aerodynamic aspects.
This paper describes the new wind load recommendation proposed by Architectural Institute of Japan in1981.The wind load is led from the consideration of buffetting phenomana of buildings in turbulent strong winds caused by tropical and temperate depressions.Two kinds of wind load are proposed;one is for structural frame designs and the other for cladding designs.Component parts of the wind load are basic annual maximum wind speed, return period of design wind speed, surface roughness, vertical wind speed profile, shape factor and gust loading factor.Cust loading factor is deduced by statistical methods proposed by Davenport and others.The recommendation also includes some comments on vortex exciting oscillations and other types of aerodynamical oscillations.