This study aims to clarify the generation mechanisms of wind-induced vibration of inclined cables using wind tunnel tests and field observation.In particular wind tunnel tests are carried out in order to clarify the influence of the axial flow related to the charactoristics of Karman vortex shedding.

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The aerodynamic vibration of stayed cables, especially rain-wind induced vibration, has been a fairly serious problem for the design of cable-stayed bridges. Form the results of wind tunnel tests, this vibration seems to be caused by some peculiar reasons such as the upper water rivulet formation on cable surface, the axial flow in a near wake of an inclined cable, and the 3-D von Karman vortex shedding along the inclined cable axis. However, the detailed mechanisms of vibration have not been obtained yet. This research aims to clarify the effect of the Karman vortex shedding on cable aerodynamic characteristics. Wind tunnel tests have been carried out for two cable models with horizontal yaw angle 0 degree and 45 degree respectively. The effect of Karman vortex shedding on galloping characteristics of cable model has been studied.

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A feedback control technique of vortex shedding behind a rectangular cylinder is investigated through three-dimensional numerical simulations. Periodic velocity excitation is applied from the cylinder surface to the separated shear flows with a time delay and feedback gain for the fluid velocity at a downstream sensor location. It is shown that the feedback excitation can suppress the vortex shedding with appropriate time delay and feedback gain. However, the vortex shedding can not be suppressed absolutely even if the feedback gain is raised, and high feedback gain amplifies the vortex shedding. This is because the strong excitation caused by the high feedback gain induces strong vortices from the leading edge of the cylinder due to feedback amplification mechanism.

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We have conducted a series of experiment to suppress aerodynamic vibration of rectangular by means of pulsating jet from the leading edges of the body.In order to clarify the mechanism ,we measured the flow velocities in the wake as well as conducted flow visualization. As a result, we have found that smooth flow is formulated in the wake when the visualization is suppressed.

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In the paper, a rectangular cylinder is employed to investigate the effect of sound on suppressing vortex oscillation. Vortex induced oscillations appearing at rectangular sections are mainly caused by unsteady separated flow from the leading edges. If the separated flow from the leading edge is controlled, vortex oscillation may be suppressed. So that sound excitation was only applied at the leading edge of rectangular cylinder in these experiments. The experimental results show that vortex oscillation of the cylinder was reduced significantly by sound excitation at a specific frequency.

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In this paper, 3D-FEM for the viscoelastic damper under the long duration loading is proposed. This analysis uses the fractional derivative, and it can simulate the temperature rise and damper stiffness decrease accuracy. From results, it is recognized that the temperature distribution inside the damper is one-dimensionally for the thickness direction of the viscoelastic damper.

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It is often observed that a panel on a roof is flattering before it scatters at the critical wind speed when the weight of the panel is balanced to the lift force. The equation of motion for the flattering of the panel is proposed in the paper under an assumption that the lift force is decreased when the panel is away from the roof. According the equation, the flattering is a kind of a free vibration of a system with a mass and a spring which relates with a air layer between the panel and the roof. The frequency of the flattering is not a function of the mass of the panel, but is the function of the flattering displacement and the critical displacement of the lift when the flattering starts.

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Elastic models of cantilevered, cable supported football stadium roofs were designed and made. Their dynamic characteristics such as natural frequency and damping were measured. The critical damping ratio was about 1%. The models were placed in a wind tunnel, and their responses in a smooth flow and direction-changing flow were measured. In both flows, the roofs at downstream side oscillated in larger amplitude than those at upstream side. No instability was observed.

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In this study, the effects of ridge shapes on wind distribution on a low-rise building's roof were examined by wind tunnel tests. Two kinds of roof's shape were tested, one was a gable roof and another was a hip roof. For each roof, three kinds of ridge shapes were prepared; one was a ridge shape without ridge tiles generally used in wind tunnel test and another were the scale models of two different height of ridge tile. Large negative peak wind pressures for the gable roofs occur at the corners of the roofs and the end of the ridge. The local pressure distribution near the ridge differs with the shape of ridge and the pressure becomes smaller as the ridge height becomes taller. For the hip roofs, large negative peak pressures occur at the corners of the roofs. The peak pressure becomes smaller as the ridge height becomes taller in the same way of the case for gable roofs.

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Wind force coefficients for the design of cladding and its immediately supporting structures of free-standing canopy roofs are proposed based on the distributions of the most critical positive and negative peak wind force coefficients regardless of wind direction. The roof area is divided into several zones and peak net pressure coefficients, both positive and negative, are given to each zone. The proposed values are compared with the results of previous studies as well as with the provisions of the AS/NZ and Japanese Standards. It is found that the Japanese Standard overestimates the design wind loads.

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Wind force coefficients for the design of main wind force resisting systems of free-standing canopy roofs are proposed based on the results of a series of wind tunnel experiments. Focus is on the axial forces in the columns as the load effect, assuming that the roof is supported by four corner columns. The design wind force coefficients are provided based on a combination of the lift and moment coefficients. The proposed wind force coefficients are verified by a good agreement with the actual values producing the maximum load effect. Furthermore, it is found that the shear force in the columns is reasonably evaluated by the proposed wind force coefficients.

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The effect of obstruction on the design wind force coefficients for free-standing canopy roof is investigated. Regarding the design wind force coefficients of the cladding and its immediately supporting structures, the effect is clearly identified in the edge regions and it becomes more significant when the ratio of the obstruction height to the mean roof height (hb/H) exceeds 0.5. Regarding the design wind force coefficients of the main wind force resisting systems, the design wind force coefficients for obstructed flow can be estimated by using the same method that was used for the clear flow case. The proposed values are verified by a good agreement with the actual wind force coefficients producing the maximum load effect. The effect of obstruction is greater on the windward half than on the leeward half. And it becomes larger once hb/H is beyond 0.5 for duo-pitched roofs. For mono-sloped roofs, the effect of obstruction is less significant.

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The damage of the traditional wooden cultural asset building by the natural disaster sometimes happens. wooden pagodas are the high rise in the traditional wooden construction, and to be exposed to the strong wind. Damage is reported to past material, and damage will be feared in the future. In this research, we experimented such as Five-Storied Pagoda of Daigo-ji Temple, The East Pagoda of Yakushi-ji Temple, and Three-Storied Pagoda of Hokki-ji Temple based on the wind tunnel to obtain basic material of the wind loading evaluation of a wooden pagodas, and evaluated those wind loadings.

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In damage of wooden pagodas there is a lot of partial damage. The possibility that partial damage causes the overall damage is large. However, there is no research to which story of wooden pagodas on big force load before. Then, in this study, using three wooden pagodas models whom can be resolved, coefficient of wind force of each story of wooden pagodas was measured by the wind tunnel test. As a result, it has been understood that wind force coefficient in wind direction in each story doesn't have the so many changes, but according to the wind force coefficient in vertical direction wind force is applied upward in the top story, and applied power downward in the bottom of the story. Moreover, it has been understood that wind force doesn't work so much at the inter-stories.

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Recently, the cases where a panel type handrail is used for a balcony etc. have increased in number.In order to carry out clear [ of the wind force which acts on these handrail panels ], simultaneous measurement of the wind pressure of a panel inside-and-outside side was carried out by the wind tunnel experiment, having used 200 Class m super-high-rise building as the model, and the peak wind force which acts on a panel was calculated.It was checked that the wind force which acts on the panels which are not in corner as a result, such as a handrail, is small.Moreover, since it was the building of the Boyd form, it checked that measured wind pressure also about the panel of the inner passage facing the Boyd side, and wind force hardly acted.Wind pressure measurement was performed also about the fence for coatings built on the roof, and it was shown that inner pressure of a roof panel can calculate wind force mostly by the pressure of a slab side.

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The wind pressure distribution on the asymmetric chamfered corner cylinder was investigated. The mean pressure coefficients became small at the chamfered corner and fluctuating pressure coefficients became large. However, the mean and fluctuating pressure coeffients became smaller at the side where with the chamfered corner in the windward. Then, the distribution of the wavelet spectrum was obtained. In the Karman vortex shedding frequency, the shearing layer approached the chamfered corner. At the side where with the chamfered corner in the windward, the vortex leave the side. It was able to be guessed that swinging of the shearing layer was caused because the development place of a right and left whirlpool changed.

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The fluctuating surface pressure measurements are made for four flat roofed building models with square plans in order to examine wind load combinations. The maximum wind force in consideration of the wind direction component and other simultaneously observed wind force components are examined, and some interesting facts regarding the wind force combinations are discussed on the basis of absolute value correlations, phase-plane expressions and so on. The maximum normal stresses in the column members of simple frame models are then examined in order to directly check the wind load combination effects.

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Authors have proposed the universal equivalent static wind load distribution simultaneously reproduced maximum load effects of structural members on large-span cantilevered roof. Maximum load effects reproduced by the universal equivalent static wind load is quite similar to that estimated by time history analysis. It is important to have this kind of equivalent static wind load in the first stage of structural design. In this study, it is discussed the universal equivalent static wind load can reproduce the maximum load effects reasonably in resembled structures. In part 1, back ground component of the load effects is discussed.

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A motion perception in buildings is not only kinematical but also acoustic and visual. And a differential between kinematical motion sensation and visual motion sensation is a main cause of unpleasant to motion. In this paper, visual motion perception lines were determined, considering length of time of seeing visual cues. And it was detected that what differentials between kinematical motion sensation and visual motion sensation, occur in each motion characteristics.Two results below were obtained. Visual motion sensation is greater than kinematical motion sensation in low frequency and low amplitude motion. Kinematical motion sensation is greater than visual motion sensation in low frequency and high amplitude motion, and high frequency motion.

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We authors have conducted a study on hydrogen explosion risk and its mitigation measures, focusing on compact hydrogen refueling stations in urban areas. In this paper, numerical analyses on hydrogen blast propagation and structural behavior of a barrier wall are executed to simulate hydrogen explosion tests. And we confirmed that the simulated overpressures meet well to the test results for all of the three test cases.

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This paper shows the applicability of the numerical methord (Autodyn2D/3D) to the prediction of the behavior of the RC walls subjected to the hydrogen exprosion. First,in order to study the fundamental phenomina about the effect of the protect wall on the explosive pressure characteristics,we investigate the peak pressure and impluse of the refrernce points not only on the ground level but also in vertical direction. Next, we show the results of the explosion test, and then compare the computational results with the experimental data.

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Wind energy forecast system based on mesoscale meteorological model and onsite measurement was proposed and following results were obtained. 1) Mesoscale model can predict the effect of local terrain and prediction error for day ahead forecast was reduced to 17 percent from 27 percent. 2) GPV data provided by Japan Meteorological Agency tends to predict typhoon earlier which causes large prediction error. 3) A new short term prediction method with onsite measurement was proposed and prediction error for six hours ahead was reduced to 9 percent from 14 percent.

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This report is describing the outline of the control wind system and the power supply control system of the hybrid power.We installed 100 micro wind generator systems and the solar cell in the apple field in Aomori Prefect. in order to develop the windbreak countermeasure using the wind turbines and labor saving technology of the agriculture using generated electricity.We installed 2 kinds of power supply control system in the green house inside in order to integrate the electricity from multiple generators.Concretely, the generated electricity is utilized for the pump and the lighting systems of hydroponic culture equipment in green house.In the summertime, the generated electricity is utilized for the lamp which decoys the moth, etc..

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The driving mechanism of Vertical Axis Wind Turbine(VAWT) is investigated numerically and experimentally. The numerical analysis is based on a DNS which is applied to the flow field including a moving aerofoils. The numerical result shows that a positive forgue is generated when an aerofoil is moving in the upstream of VAWT. In this situation, the leading edge of an aerofoil has a strong negative pressure and thus the forgue is generated. For the application of 2-D Wind lens(a collection and acceralation device) to VAWT, the output performance remarkably improves. becouse of an increase in approaching wind speed.

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The effects of freestream turbulence on the turbine wake characteristics have been experimentally investigate with a wind tunnel. Using a large-scale turbulence grid, the high level turbulence involved in the freestream was generated. The turbulence measurements indicate that the wake structure of wind turbine markedly changes with an increase in freestream turbulence. This is caused by the increases in the critical Reynolds for an aerofoil with the intensity of velocity fluctuation in freestream.

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In order to investigate turbulence characteristics in the wake of a wind turbine, a three-dimensional numerical simulation was performed. As a result, a complex eddy structure was reproduced.

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Wind tunnel experiment on the nacelle of wind turbine system is reported. Part I reports the result of wind force measurements.

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Peak pressure coefficients on nacelle of wind turbine were measured to estimate design wind load on components of nacelle. AIJ introduces peak pressure coefficients for components and cladding of buildings in Recommendations for Loads on Buildings(2004), however, their values appear to be underestimated. Because their peak pressure coefficients are for common architectural structures standing on the ground, not for nacelle enclosure mounted tower. The results were that minimum peak pressure coefficient distribution is rather similar to pressure distribution on roof of rectangular buildings over 45m height recommended by AIJ. But values appear to be slightly larger than AIJ recommendation as expected.

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In this paper we describe the characteristics of wind forces acting on a propeller-type standstill wind turbine with three blades. The wind forces were investigated using wind tunnel tests. The test parameters were wind tunnel flow (grid turbulent flow and uniform flow), pitch angle of the blades, stationary blade positions. As a result, the wind force coefficients acting on the standstill wind turbine at a position where one blade corresponded to a tower were differed from those at the other blade positions.

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Natural frequency and dumping ratio was made clear by onsite measurement and eigenvalue analysis. Maximum bending moment at the root of the tower was calculated by wind response analysis and compared with measurement.

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Proposed method considering vibration property of blade and toiwer can evaluate the wind load for all the wind direction. Conventional method might underestimates the wind load for some wind direction.

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