Strong winds due to Typhoon Jebi (2018) caused many human injuries. This paper reported that ages and injury causation of victims to reduce human damage caused by typhoons. The most injuries were caused by a fall due to strong winds, especially in the 50s or more. Also, many injuries due to falling down from the roof and such were in older people over 60s. On the other hand, many injured people in their 40s were from wind-borne debris and overturning of cars and so on. Focusing on the extent of injury, accidents such as falls from roof were likely to lead to serious damage, but injuries from falls were often minor. Damage due to debris caused serious damage in some cases. In order to reduce human damage, it is necessary to call attention to behavior under strong winds.

T1821, which landed to southern Tokushima as a very strong typhoon on September 4, left tremendous wind damage to Kinki area. In this study, aerial survey using small aircraft was carried out, and the distribution of blue sheets covering the roof of residences in southern Osaka Pref. and northern Wakayama Pref. was investigated. In addition, the number of damaged houses in northern Wakayama Pref. was estimated from the relationship between the number of blue sheets and the number of damaged residents in southern Osaka Pref.

In these years, meteorological observation using the doppler lidar is applied in many fields. The evaluation on the long term performance of the Doppler lidar needs the measurement precision and the data missing rate. Although many investigation organizations tested the performance of the doppler lidar and had generally good results, the duration of the test was relatively short. Therefore, it is unknown whether the doppler Lidar is applicable to the long term meteorological observation. In this study, we carried out parallel observation of multiple doppler lidars at the coastal region of the Pacific Ocaen in the Kinki district in a year. This paper reports the result of examination on relationship between the data missing rate and Precipitation.

Parallel observations for one year with two different Doppler lidars DIABREZZA and StreamLine Pro were conducted at the coastal area of the Pacific Ocean in the Kinki district. In this paper, we investigated the vertical profile of wind speed and the turbulent intensity for the parallel observation of Doppler lidar in typhoon No.21(2018). As a result, it was found that the observational accuracy of Doppler lidar at typhoon did not differ depending on model. Characteristics of the vertical profile of the wind speed and the turbulent intensity at the time of typhoon passing were clarified.

We estimated wind fields around Typhoon 'Jebi' caused strong wind hazard in Kinki area on 4 September 2018, by making dual-Doppler analysis with Airport Doppler radar dara at Itami Airport and Kansai Airport. The results showed that Ekman spiral was observed in lower layer and velocity peak was observed at 0.5 km AGL. At this height, strong wind of 67.6 m/s in velocity was observed when the maximum instantaneous wind velocity was observed at Osaka Observatory.

In this study, I reserch climatological feature of foehn phenomenon occurred in Itoigawa and for strong winds blown during Itoigawa fire that occurred on December 22, 2016, I use WRF to do Reproduction experiment. As a result of the climatological survey, it is revealed that many foehn phenomenon in Itoigawa is occured when the pressure gradient takes south to north. Moreover, from the results of the experiment using WRF, it is suggested that the strong wind is driven the downslope wind effect that the wind blows down from the saddle between the two mountains and the contraction effect by the wind passing through the two mountains.

A fundamental wind tunnel experiment to measure impact forces by wind-blown sphere was conducted. An aluminum plate supported by four piezoelectric load cells was embedded in the floor of wind tunnel duct. The sphere of which diameter is 25mm and the mass is 3.2g was made by a 3D printer. As a preliminary experiment, the relation between the impact force on a single load cell and four load cells supporting the aluminum plate was obtained. Also equations to estimate the hitting points are introduced based on a series of measurement of impact force on the plate. A wind tunnel experiment was conducted to examine the estimation of the hitting locations.

Damage to buildings during strong wind is caused by flying debris in many cases. In order to reduce the damage, impact of flying debris needs to be estimated by measuring its aerodynamic characteristics. Aerodynamic characteristics of flying debris have already been measured in wind tunnel experiment when wind direction and wind speed do not change; however, there is little information of those when wind forces acting on debris change from moment to moment. This study aims to clarify the aerodynamic characteristics of flying debris by direct measurement. A stand-alone measuring device was built in a model of debris. By dropping the model from 50 meters height in a dome with windless condition, wind force coefficients were measured. The measured wind force coefficients were compared with those measured in wind tunnel experiment.

Wind tunnel test was carried out to investigate the wind speed of gravel dispertion. Model gravel was distributed on the surface of gravel and asphalt settled in the wind tunnel, and the floor. Wind speeds of gravel dispertion were measured. The variation of wind speed for dispertion with the spacing of model gravel and the configuration of surface was investigated.

Airborne salt is one of the key factors that promote the corrosion of steel bridges. Thus, before the construction of a new bridge, it is desirable to accurately evaluate the amount of airborne salt at the bridge site. The dry gauze method is most often used to measure the amount of airborne salt in Japan. However, the collection efficiency of the dry gauze method for salt particles has not been clarified sufficiently because of complicated airflows around the device. Therefore, to clarify the collection efficiency of the dry gauze method, the authors simulated flow fields around the device of the dry gauze method by CFD. Additionally, using flow fields simulated, particle tracking was carried out to evaluate the behavior of salt particles in the vicinity of the collection device. The results show that some of salt particles flow down around the device without adhering to the gauze because of the complicated flow field.

Evaluating salt amounts adhering to bridge surfaces is important for effective maintenance. However, methods for reducing salt amounts have not been sufficiently investigated yet. In this study, the authors proposed installing an object on the ground to change air flows around a body, and investigated its effect on the movements of airborne salt particles using CFD. A rectangular cylinder with a side ratio of 2.5 was employed. It was clarified that the proposed method is possibly applicable when the distance between the rectangular cylinder and an object is less than around 6D, and that a ground object under the rectangular cylinder affects the lower separation flow to reduce the salt amounts on the lower surface of the rectangular cylinder.

"Evaluation scale based on the exceedance probability of daily maximum instantaneous wind speed" by Murakami et al. is widely used as the wind environment evaluation scale of the pedestrian height around building. However, the commonly used calculation method of the exceedance probability of daily maximum instantaneous wind speed remains the following two problems. First, depending on the characteristics of the airflow around the building, the day maximum wind speed at the evaluation point is not necessarily caused by the day maximum of the natural wind. Furthermore, 16 wind direction division intervals may not be so sufficient that there is a possibility that the maximum wind speed at the evaluation point will not be captured. Therefore, in order to solve the above problems, we proposed an improved method to evaluate the exceedance probability of daily maximum instantaneous wind speed. Based on the meteorological data of Tokyo and CFD calculation, we calculated the daily maximum wind speed around the 2:1:1 prismatic model and the trend of underestimation of the exceedance probability by the conventional method is also shown in this paper.

Weather data recorded by nearby weather stations are commonly used in wind and outdoor thermal environment evaluation. However, due to the location and surrounding buildings of the site, the wind and thermal environments are difficult to evaluate properly. A field measurement in a green space located in industrial area was carried out, the measurement data were compared to 2 nearby AMeDAS weather stations, and the differences were analyzed. In most of the summer sunny days, northerly winds blew at night and southerly winds blew in the day at all the 3 locations. The air temperature differences during daytime between measurement point and AMeDAS in the south direction were merely changed when wind direction changed.

In this study, unbalanced snow accumulation on a two-level flat-roof building was predicted using computational fluid dynamics (CFD). First, the snow depth distribution on the lower roof was predicted by using a snowdrift model previously proposed by the authors without considering the effects of snow depth change on the flow field. Comparisons of the predicted snow depths with observational data indicated that the observational data of snow depth on the lower roofs could generally be reproduced using the proposed CFD simulation method. However, the specific undulations of snow near the roof step were not well reproduced by this method. Next, the effects of snow depth change on the flow field were considered through phased calculations. The study confirmed that the prediction accuracy was improved by considering these effects.

This study carifies the effect of weather disturbance on the turubulent field of urban boundary layer by LES. First, the inflow condition assuming atmospheric boundary layer is generated by WRF-LES and spatial filtering and rescaling method and the inflow data is connected to calculation domain for BCM-LES. As a result of comparison between cases using inflow condition with and without weather disturbance, it is confirmed that wind velocity fluctuation derived from weather disturbance appears in the upper part of urban boundary layer and it affects the turbulence field above the urban roughness.

A wind climate assessment method considering the atmospheric stability and the effect of terrain was proposed by using numerical flow simulation and Monin-Obukhov simularity theory. Offshore Choshi, the north easeterly wind is srongly affected by terrain and the southerly wind is affected by the atmospheric stability, which could not be accurately simulated by comventional methods. Proposed method can predict the wind profile and satisfy the criteria of wind climate assessment.

Turbulent flow fields in an urban area are investigated by LES model. Predicted mean wind speed and turbulence intensity show good agreement with the measured data from the wind tunnel test.

The present paper investigates the aerodynamic stability on long-span roofs based on a computational fluid dynamics (CFD) analysis with large eddy simulation (LES). Three kinds of roofs, i.e. flat, cylindrical and suspended roofs, are tested. A smooth uniform flow and a turbulent boundary layer are used to understand the effect of inflow turbulence on the roof’s vibration. In the present paper, forced vibration tests in the first symmetric and anti-symmetric modes are carried out to clarify the stability of long-span roofs, and the energy contribution of the flow to the roof during the vibration period is computed. Finally, the critical condition which induces the aerodynamically unstable vibration is presented for each roof shape based on the energy contribution.

Wind pressure models for wind tunnel experiments used in structural design of high-rise buildings are often reproduced with deformation while the effect of the detailed shape of the facade on wind force measurement is unknown. The balcony is one of the shapes that are often reproduced deformed. This report is a case study that confirms the effect of the following three points on the layer wind force. (1) difference in balcony reproduction, (2) presence / absence of balcony measurement, (3) difference in measurement point arrangement. When the balcony shape is not reproduced it gives an overvaluation to the mean layer wind force and its standard deviation, and when reproducing the balcony as volume it gave underestimation. The wind force borne by the balcony itself was small. Also, in the case where the measurement point is placed on the inside of the balcony and the case where the measurement point is arranged outside the balcony, the influence on the layer wind force was minor in either case.

In recent years, optimization techniques for improving performance and streamlining designs are utilized in various fields. In the field of wind engineering, it is trying to utilize it when designing a structure advantageous to wind force. However, in the optimization calculation requiring more than 1000 cases to obtain the optimal solution, besides utilizing the RANS with a small calculation load, there is no option at present. Therefore, in this study, RANS was combined with the optimization calculation on the shape and layout of the building to reduce the wind force, and compared with the past experimental research. As a result, we combined RANS with optimization technology to grasp the building shape that is relatively advantageous against wind force.

The purpose of this study is to identify the effect of model support conditions for two square cylinders in a tandem arrangement on aerodynamic vibrations. Based on the supposition of actual structures, spring-supported tests, with both square cylinders elastically suspended, were conducted. Comparing with the test results, spring-supported tests, with one suspended elastically and the other fixed, were carried out in order to clarify the effects of the differences of support conditions on aerodynamic vibration characteristics. Furthermore, flow visualization tests were performed for consideration from the results of the spring-supported test.

Aerodynamic Property of Rectangular Cross Section Beam with Large Deflection by Self-Weight was investigated using wind tunnel. Wind load at fixed end and accelaration at free end were measured with parameter of wind speed and angle of attack. Wind force slope around at 0° is 25% of theoretical value of plate wing. Flutuating coefficient of wind force has maximumu value at -9° and 8°.

Previous researches on aerodynamic vibrations were limited to very small amplitudes. Thus, the responses characteristics with large amplitudes at a high reduced wind speed region were investigated in term of velocity of relative angle of attack (α) using a rectangular cylinder with a side ratio of 5, in which torsional flutter may occur. In this study, the new formulation of the aerodynamic forces based on α was suggested. The aerodynamic forces of the model with constant torsional velocity agree with the unsteady aerodynamic forces with torsional 1DOF sinusoidal vibrations. The effect of α on torsional vibrations was revealed. Furthermore, the results of the time series analysis by using the aerodynamic forces based on α coincide with the experimental results under 3DOF condition.

This research investigated the relationship between the size of side openings and the aerodynamic performance. To simplify the discussion, the rectangular cylinder with a side ratio of 2 was applied. For the different opening area ratio (OR), the aerodynamic performance was monitored through vertical one degree of freedom (1DOF) free vibration tests, forced vibration test and aerodynamic force test. To further investigate characteristics of the flow field around the model, time-averaged streamline was calculated through flow visualization experiments and PIV analysis. With the increase of OR, the critical wind velocity gradually increased. Meanwhile, the aerodynamic damping increased with the increase of OR from 0 to 0.75 and then decrease with OR. It can be explained by that the shear layer approached the trailing edge of the model with the increase of OR and finally reattached on the side surface from OR = 0.875.

Global warming influences sea surface temperature which intensifies typhoons and may change extreme value distribution of wind speed. In order to simulate typhoons affected by sea surface temperature, full-track type typhoon simulation is very effective measures. The effect of sea surface temperature on the extreme value distribution was evaluated by a past typhoon simulation. However, errors tend to accumulate because the typhoon paths simulated is long. In this study, a new model of the central pressure difference was proposed. The result showed that central pressure calculated by the new model is close to observed values.

As a method to estimate the daily maximum wind instantaneous wind speed from the daily maximum wind speed, estimation of gust factor using topographic factor analysis was performed. In the previous study, only data observed at meteorological offices and special automated weather stations was used, however, surroudings of these stations are often open terrain. Therefore, to estimate the gust factor, we performed topographic factor analysis with the observation data of AMeDAS which has a wide variety of surrounding terrain. As a result, the estimation error decreased by about 50%, and it was shown that the day maximum instantaneous wind speed can be estimated more certainly.

The plains of Gunma and Saitama prefectures have a high density ground surface meteorological observation network consisting of POTEKA weather stations with around 150 points and a resolution of approximately 2 km. These plains have a climatological feature that a cumulonimbus is generated over the surrounding mountains and proceeds over the plains with the growth and causes gusts such as downbursts and gust fronts in the summer. The high density ground surface meteorological observation network has succeeded in observing 13 cases of gusts, which included 5 cases in the F1 category (Fujita Scale) and the JEF1 category (Japanese Enhanced Fujita Scale) for about 6 years since July 2013. In the downburst cases of the F1 on June 15, 2015 and the JEF1 on July 14, 2016 which were substantially damaging, the localized transition of wind direction / speed was observed. Moreover, it was confirmed the sign of the divergent wind by the downdraft of downburst.

Tornado is one of the factors of strong wind damage of buildings in Japan. In order to reduce the damage of tornado, it is necessary to investigate what property the tornado flow has. The three components of tornado vortex velocity fields by using the tornado-like flow simulator were measured with a stereo PIV system that was constructed in Tokyo Polytechnic University. Effects on roughness to mean velocity distribution were investigated. As a result, positions of the absolute maximum value of the tangential wind speed and the radial wind speed that had roughness farther from the floor than the without roughness. A position of the vertical wind speed that downflow reached farther from the floor than the without roughness. The vertical distribution of turbulence intensity tended to be different from general atmospheric boundary laminar flow.

In the morning on 30 September when the typhoon ‘Trami’ approaching Kochi, two tornadoes occurred near Nagahama area in Kochi. The present study is aims to estimate tornado intensity by using photogrammetric analysis. We also compare the results with the observation data by Susaki radar in Kochi University. The results show that the first tornado is stronger than the second tornado. The circulation estimated from the width of water splash is one-third of that estimated from the bottom height of funnel cloud. And We find that any tornado damage would not occur for the tornado of less than 2500 m²/s in circulation.

In the background that rooftop signboards are often not properly designed with wind resistance, the authors have been studying the peak wind force coefficient which acts on rooftop signboards for the purpose of reducing the wind damage. Our previous paper shows that large peak wind force is generated at the end of the rooftop signboard. And it was shown that the shape of the building, the positional relation between the corner of the building and the rooftop signboard greatly influence the positive peak wind force at the edge of the rooftop signboard. On the other hand, there are several previous studies on wind force acting on a flat plate on the ground. These show that the ratio (b / h) of the width b and the height h of the flat plate influences the wind force of the flat plate. In this paper, for the purpose of clarifying the influence of building against the positive peak wind force at the edge of the rooftop signboard, we conducted experiments on the status of the signboard alone. Compare with the results of the signboard installed on the building and consider the influence of the building.

Recently, scaffolding with noise barrier panels is often used for demolition works of old buildings. However, collapsing accidents occur due to strong wind, probably because the wind forces on the panel are not properly considered. To clarity the wind force characteristics, a wind tunnel test was conducted in a simulated boundary layer flow.The experimental results showed force coefficients of the experiment were larger than those of a past research using the model with slits. Standard deviations in case of θ=0° are relatively larger than that of other wind directions. The maximum value occurred in case of θ=22.5°. The minimum value occurred in case of θ=135°. Standard deviations in points where the maximum and minimum values occurred were larger than that in the same sheets.

As one of the causes of metal roofing failure due to wind loads, there is failure at the edge of metal roof panel or metal clip for fixing metal roof panel. MSRW 2014, which summaries the details of construction and maintenance methods for metal roof building components which are not covered in SSR 2007 and SSW 2011, presents the test methods and results in order to determine the metal panel strength for such failure. However, only 1 test specimen for each test parameter was employed in order to understand how this failure occurs and the effect of each parameter in general. Hence, the present study performs a similar test to determine the maximum resistance of metal panel under such failure but with more test specimens (min 5) for obtaining statistically reliable data as well as suggesting its estimation equations.

In this study, the author carried out the finite element analysis using models of connection between metal roofing component and timber beam, which is to understand the mechanism and process of deformation in models under uplift loading. The successive loading was applied on the top of models in the same way as load tests in the previous study. It was confirmed that the analysis obtains almost the same process of deformation as observed in load tests, but that there is difference in displacement from the result of load tests. Additional verification of analytical condition should be needed for the improvement of the analysis.

In a hot area, such as Okinawa Island, use of net-house is going to spread recently, however severe typhoons sometimes destroy many green houses as well as net-houses. Field observation was conducted, to develop the wind design method for net-house against strong wind. The results showed that instantaneous large wind force sometimes acted on the net. Then, large blow up force on the roof occurred, and the wind force per unit area on the roof closed to the wind force of the leeward wall. The phenomenon was guessed to be affected by the influence of heavy rain covered the net surface. On the other hand, wind-sheltering effect through the net yielded to 35 percentages or less.

The Japan Meteorological Agency (JMA) has formulated and implemented a Japanese version of the enhanced Fujita scale (JEF scale) in April 2016 corresponding to buildings and the other damage in Japan. However, in the current JEF scale, there are cases where the degree of damage (DOD) cannot apply and is not subject to assessment. For example, the damage of the storage (Damage Index = 10) is limited for the case which is not fixed to the ground, and if it is fixed, JEF scale cannot apply. However, storage manufacturers have recommended them to fix to the ground. In this study, the damaged wind speed for the fixed storage was estimated based on the actual strength of connection part of the storage and the ground by the assembly test for the purpose of estimating the damage generated wind speed and adding it to the JEF scale.

Recently, usage needs of outdoor space is increasing. The authors thought it necessary to investigate how it feeling about outdoor wind environment on variety situations. Questionnaire survey about wind velocity and feeling have been carried out in autumn 2017, spring & autumn 2018.In this paper, the part of the results in autumn 2018 is indicated. The results of subjective evaluations of wind strength is correlated with mean wind velocity.There was a slightly different trend in subjects responses that how suitable the experienced wind for each activity content.

In recent years, increasing access to computing power has led to the prediction of pedestrian-wind-environment using LES. In the assessment for pedestrian-wind-environment based on the RANS model, the maximum instantaneous wind speed was estimated by multiplying the mean wind speed with the gust factor. However, LES can predict the instantaneous wind speed directly. In this study, we conducted LES of the flow field around an isolated building and analyzed the cross-correlation between the wind speed fluctuation in the windward of the building and the pedestrian height around the building. Then, we focused on a strong wind event in the side of the building and applied a back trajectory method to estimate pathline of the strong wind in the side of the building. Based on the back trajectory method, it is indicated that the air cell for the strong wind directly flowed from the middle height of the building in the windward to the windward corner of the building without impinging the windward wall of the building in this event.

Large-eddy simulation (LES) was conducted to analyze the flow around an isolated building model in an urban boundary layer. Based on the LES results, gust factor (GF) and peak factor (PF) at the pedestrian level were analyzed. Although the mean wind speed was highest in the vicinity of the building corner on the upstream side, GF and PF were relatively small at that point. The statistical uncertainty of GF tends to decrease with increasing mean wind speed. However, that of PF shows similar magnitude at any point and has no clear relationship with the wind speed.

High temperature gas containing pollutant at high concentration is exhausted around the building due to operation of the emergency generator. Since the regular test operation is performed, there is a growing safety and health risk to people and buildings. In this study, we conducted a diffusion experiment of light gas and neutral gas by wind tunnel experiment and compared mean concentration, intensity of concentration fluctuation and peak concentration. High mean concentrations were observed in both cases near the leeward wall due to backflow in the wake region. Due to buoyancy, light gas showed a relatively lower concentration than neutral gas, but concentration fluctuation intensity and maximum concentration ratio were about the same.

The authors conducted LES analysis of the flow field in the city block model using three kinds of incoming fluctuating winds with different creation methods as previously reported and compared with the wind tunnel experiment result. As a result, in the place surrounded by the building, the flow field was hardly dependent on the way of creating the influent wind. In this report, we investigated the influence of the method of creating inflow fluctuating wind on the diffusion field using the same city block model. As a result, it is considered that influence on the diffusion field is small in the place disturbed by the block, the way of creating the inflow fluctuating wind is small. So far, we have compared statistical values and so on. In the future we will study the reason why the time mean value of dimensionless concentration is different and the reason why the standard deviation of the wind tunnel experiment is lower than the LES analysis by the wind tunnel experiment and the LES analysis by using spectral analysis and the like.

In previous study, the time-averaged wind pressure coefficient on the wall surface is used to calculate and evaluate the natural ventilation rate using the external wind as the driving force, and the wind pressure fluctuation caused by the wind is not taken into consideration. In this research, the building models in the Marunouchi district of Chiyoda-ku, Tokyo are analyzed using Large-Eddy Simulation (LES). By the airflow network calculation based on the variation of the wind pressure coefficient, the ventilation rates are calculated. The mean wind pressure coefficient and the instantaneous wind pressure coefficient are using for the calculation. The natural ventilation rate caused by the wind pressure fluctuation are reported

Atmospheric boundary layer flow impinging on a large cylindrical structure often reaches a supercritical Reynolds number. The flow in this region on the wind tunnel scale is difficult due to limitation of wind tunnel performance. Generally, in order to reproduce the drag coefficient of the transcritical Reynolds number region, a method of providing a roughness on the cylindrical surface is used. Many experiments have been reported for the flow around a cylinder with roughness, but few analysis examples using LES have been published. Therefore, in this paper, for the substitution by the numerical analysis of the experiment for the chimney, numerical analysis of the flow around the two - dimensional cylinder with roughness using LES, the aerodynamic coefficient was obtained and compared with the experimental result.

When we compute the flow around an object having an appendage directly by CFD, especially when its shape is a curve or a curved surface, in order to prevent the shape approximation error not to affect the result, a computational mesh which enough resolves near the appendage is required. On the other hand, the isogeometric analysis method proposed by Hughes et al. recently eliminates shape approximation errors and could be strict shape representation even if a small number of elements in numerical simulations. In the present study, we developed an isogeometric fluid analysis method and analyzed around a circular cylinder with an appendage for validation. As a result, a slight difference in flow fields when an appendage exists was observed.

The purpose of the chimney is to diffuse the exhaust gas discharged from power plants and factories over the sky and to reduce the concentration of exhaust gas reaching the ground. Since the diameter and height of the chimney are determined so that the exhaust gas concentration satisfy the environmental standards, it is not unusual the case that the aspect ratio becomes 20 or more. In this research, in order to clarify the aerodynamic properties working on a cylindrical shape with a large aspect ratio, wind tunnel experiments were carried out, mainly focusing on wind pressure distribution.

Wake galloping and wake-induced flutter appear in such parallel circular cylinder structures such as cables which are stayed long-span bridges. The research on these aerodynamic instabilities have been done so far, however, the mechanism of that has not perfectly been revealed. Here we show the relationships between the arrangement of 2 cylinders and mechanisms and between the reduced wind velocity and mechanisms of these aerodynamic instabilities gained from forced vibration tests and 2 DOF flutter analysis. It is revealed that the mechanisms of aerodynamic vibrations depending on a slight difference in the arrangement of 2 cylinders. Moreover, It is found that due to the change of the value of the unsteady aerodynamic derivative H1* as the reduced wind velocity changes, there is an arrangement in which vibration of different mechanisms of aerodynamic vibrations occurs.

In this study, to investigate unsteady aerodynamic force characteristics of the four-bundled conductors, aerodynamic measurement tests were performed using rotary devices that can input arbitrary waveforms. The aerodynamic force coefficients, which are defined as two-variables function of the angle of attack and the non-dimensional angular velocity, were measured in the tests with constant angular velocity. Then, the validity of the aerodynamic formulation using these two variables was confirmed by comparing the unsteady aerodynamic coefficients obtained by the forced vibration tests with sinusoidal wave.

Snow accretion and wind blowing on conductors causes short circuit and fatigue by galloping. To understand galloping by observation, estimating vibration modes by tension is effective. In this paper, the relationship between displacement and tension of four-bundled conductor is discussed by using measured value in excitation tests. In the case of vibration which have odd antinodes, natural frequencies of tension show good agreement with those of displacement. However, it doesn't apply to even antinodes. To estimate vibration modes correctly, considering magnitude of the tension fluctuation is necessary.

The response of a medium-size wind turbine in cold climate was analyzed considering low temperature and icing, in order to clarify how they affect the results. The increase in the mass of the blades by icing increased the axial force at blade root. The eccentricity due to icing of two blades might have caused unstable rotation and larger fluctuations of the rotor power.