The structural design of transmission line requires wind information under severe wind load. However, wind data which has been observed only over short periods at a transmission line in high altitude mountainous terrain is not sufficient for determining design wind speed. We analyzed a correlation between wind records observed along a transmission line and its nearby observation points, for the purpose of utilizing long-term wind records at the surroundings points, such as Meteorological Observatories, effectively. Our results showed high correlations between wind at the transmission line and the nearby points in a certain range of wind speed and direction. In addition, it was found that WRF, one of the well-known meso-scale atmospheric models, reproduced wind distribution around the transmission lines brought about by Typhoon Usagi(0705) rather well. The winds measured at several transmission lines corresponded well to reproduced winds by model.

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For the wind resistant design of the structures built on the complex terrain, it is necessary to take into consideration not only the amplified level of mean wind velocity but also the variation of turbulent intensity. Turbulent intensity is very important for fatigue load. Inorder to accurately predict the turbulent statistics by CFD, we should use LES which can solve unsteady flow fields as a simulation model. So, we performed LES over an acually existent complex terrain, and verified the accuracy of prediction for turbulent characteristics, especially focusing on the turbulent intensity, in comparisonwith the observational data in this paper. Also, we considered the influence of surface roughness and mesh resolution near the terrain on the turbulent flow field.

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When considering the wind-resistant design of low-rise buildings, it is important to evaluate the wind loads accurately. It is necessary to understand in detail the characteristics of natural winds near the ground surface. In the present study, a quantitative estimation method is developed to evaluate the turbulence of winds near the ground surface on the basis of field measurements at various points. The characteristics of surface roughness are evaluated on the basis of several factors obtained from a building information database, and the relationship between these factors and gust factor is discussed based on the observation height.

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A weather derivative was utilized out of concern for unscheduled expenditures and losses in the international gardening and landscaping exhibition Japan flora 2000, in which the index was the number of days meeting with strong wind. In this study, the effect of strong wind on the decrease in the exhibition visitor number is investigated through the analysis for the correlation between the daily visitor numbers and the daily maximum wind speeds. The price of the weather derivative is estimated with the payout simulation using a theoretical formula substituted the wind speed data recorded in the past. The simulation result is compared with the contract condition of the weather derivative, and the validity of the contract deposit is discussed.

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In this study, we attempted to enable prediction of pollutant concentration in the non-neutral atmospheric condition from wind tunnel experiments and CFD simulations of neutral atmospheric condition only, generalization that expressed the effect of atmospheric stability on pollutant concentration within urban street canyons. We conducted the effect of atmospheric stability on pollutant concentration within urban street canyons from both wind tunnel experiments and CFD simulations under different atmospheric stability conditions. Similar tendencies can be found by wind tunnel experiments and CFD simulations. A “stability effect ratio” of pollutant concentration (SER_C*=C*/C*n) increased with increase in Bulk Richardson number and SER_C* was probably independent of the locations and flow patterns. Thus SER_C* was proposed as an index expressing the effect of atmospheric stability on pollutant concentration.

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This study aims to verify prediction of pollutant concentration in urban area based on wind
tunnel  experiment  by  comparing  experimental  results  for  a  small-scale  model  of  Tokyo
Polytechnic  University  area  with  field  measurement  data.  Wind  tunnel  experiment  was
conducted  under  various  conditions  of  wind  velocity  and  pollutant  emission  rates  to
investigate effects of these factors on the prediction accuracy. It is showed that normalized
non-dimensional  concentration  obtained  by  wind  tunnel  experiment  agreed  well  with  the
field measurement data. It is also confirmed that normalized non-dimensional concentration
is nearly independent of wind velocity and pollutant emission rate.

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The Japan Aerospace Exploration Agency (JAXA) has conducted wind measurements over urban
canopy  to  build  numerical  wind  model  for  roof-top  heliport  operation  on  high-rise  building.
Doppler lidar and the JAXA’s research helicopter which is capable of measuring winds at 40Hz
were used to measure winds aloft. In the measurement, larger power exponent of wind speed profile, more  intensive  turbulent  intensity  and  smaller  turbulence  scale  length  were  observed  in  urban canopy  compared  to  the  existing  standard.  These  acquired  data  will  be  incorporated  into  the
numerical wind model.

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Vertical profiles of horizontal wind speed in urban area (Shibuya, Tokyo), where is surrounded by many types and heights of buildings, were obtained using a Doppler lidar system. We tried to estimate roughness length and zero plane displacement height by the non-linear least square fitting method with 10 minutes mean profiles fit to the theoretical log-law wind profile. As the results, the roughness length and the zero plane displacement height around the site were estimated to 0.60±0.88m and 26.8±8.8m above the ground, respectively. The roughness length and the zero plane displacement height, derived by another method using the building floor information of GIS database of the Tokyo Metropolitan government, were estimated to 0.74m and 31.7m, respectively.

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Zero-plane displacement height over urban canopy was measured in Yoyogi Tokyo. We used  temperature  variance  method,  which determines  the displacement height  from  the measured variance of temperature at a single level. The measured displacement height was 24 to 35 m which is much larger than the mean building height. This exceeding over mean building  height  should  be  due  to  the  height  variation  of  buildings  in  the  canopy.  The measured displacement height normalized by the maximum building height agreed with a previous numerical model study. The displacement height was largest at the area with the skyscrapers and the least value was found in the park area.

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This paper aims to propose a method to generate turbulent fluctuations of wind velocity and air temperature under unstable condition. The artificially generated turbulent fluctuations satisfy not only the prescribed profiles of turbulent fluxes but also the prescribed spatial and time correlations. Turbulent fluctuations were generated by this method using the turbulent fluxes and turbulent time scale under unstable condition measured at COSMO site. The statistics of the generated turbulent-fluctuations are analyzed to verify the reproducibility by comparing them with the measurement data obtained in COSMO.

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In this study, in order to prepare standard statistical wind data for assessment of pedestrian wind environment, we aimed to use WRF (The Weather Research and Forecasting Model), a meso-scale simulation model, as an alternative to direct observation. Effect of calculation conditions such as physics schemes, size of computational domain, and nudging were investigated by comparing calculated result with observation data measured by Doppler Lidar. The comparison showed that correspondence of calculation result with observation data is remarkably improved by using Noah Land Surface Model. Weibull parameters derived from calculated values agreed well with those of observation data. It means that occurrence frequency of wind velocity not only for all wind directions but also for each wind direction was accurately predicted by WRF. When using a large computational domain, correspondence between calculated and observed results became worse. But, by adopting nudging, calculated results approached observed results even when a large computational domain was used. Although power law index α calculated by WRF slightly underestimated as compared with the observed value, variation tendency of α versus wind direction was well captured by WRF.

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Building distance is closely related to wind and thermal environments around buildings. Long distance can enhance ventilation between buildings, while short distance can contribute to providing shade. In this study, thermal environment around buildings is investigated by changing building distance. Since the effects of sun-shading are associated with latitude, Guangzhou and Wuhan, China and Sendai, Japan are selected.

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The research on piloti space, which is an important part of building in area with hot and humid summer, has not been studied sufficiently. In this paper, non-isothermal CFD analysis for residential buildings of row layout in Wuhan was carried out using STAR-CD V3.26. Through comparing the results of basic case and four cases with different piloti arrangements, it was clarified that piloti set in the two ends of building is the optimal piloti arrangement. Then the relationship between piloti ratio and wind environment was investigated based on the optimal piloti arrangement. Finally, the wind environments were evaluated using a criteria for assessing wind-induced discomfort considering temperature effect. When piloti ratio is more than 12% in residential area of row layout in Wuhan, the wind-induced comfort can be realized.

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This study aims to investigate and clarify the influential factors for human thermal sensation in outdoor space. Field measurements of thermal environments and questionnaire survey of thermal comfort were carried out to find out the principal causes that affected human thermal comfort in and around green and water space. Additionally, coupled analyses of CFD simulation and radiation calculation were carried out to predict the wind and thermal environment. A new method for analyzing the contributions of climatic factors and heat flux due to each element in the heat balance equation of human body to SET* values was proposed and applied it to clarify the influence of green and water space. 

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Traditionally, cross-ventilation is considered as one of the most effective means for promoting better indoor thermal comfort in Japan. The cooling breeze effects due to natural wind fluctuation on skin temperature, core temperature and sweat evaporation from the human body are very important in evaluating thermal comfort in a cross-ventilated environment. Experimental investigation was carried out under sinusoidal wind flow conditions using a climate controllable wind tunnel. It was found that skin temperature, core temperature and sweating rate had a high correlation with sinusoidal wave flow frequency.

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This study investigates the characteristics of surface winds that precede the occurrence of summertime, local-scale rain events over the Nobi Plain under synoptically undisturbed conditions with the use of operational meteorological data from 2003 to 2010. By extracting the undisturbed conditions, we found that afternoon rain events develop in the northern part of the plain, migrating from the mountainous regions surrounding the plain. A significant difference was found for the surface wind fields before the rain events: on fine days surface winds in the plain were southwesterly, directed eastward in accordance of local circulation thermally induced by central mountain regions; on rainy days surface winds in the plain were southerly, directed toward the mountain region to the north of the plain. In other words, the difference in the surface wind fields can be used to diagnose a potential for the development of the afternoon rain events.

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Wind power energy densities and annual productions generated by middle-scale windmill facilities in Kyushu were estimated based on information of fluctuations of wind direction and speed minutely recorded by NeWMeK using power transmission lines. It was found that several places of NeWMeK provided available annual means and stable directions of wind for wind power generation although their fluctuations of wind were not low. Production of electricity based on low wind speed with large fluctuations accounts for a large percentage of whole production. So, actual electric power generation may not reach the potential wind energy estimated using only annual mean wind speed record.  Many windmill facilities which were located at places with big turbulence of wind will not exhibit the best performance in power generation.

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In small wind turbines, the load torque is often considered to be proportional to the square of the rotational speed. The load torque gain, as a proportional constant, includes the reference air density and other constant parameters. A constant gain assumes there is no variation in the air density. In a real situation, the air density is a function of time due to the variation of the atmospheric pressure, temperature, and humidity. Because of this air density variation, an operating condition based on a constant gain may not be maintained. We examine the effect of air density variation on the operating tip-speed ratio, which is a quantity characterizing the operating condition. The effects of air density variation on both the operating tip-speed ratio and power of a wind turbine are calculated using the modeled differential equation.

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The purpose of this study is to improve efficiency of a solar tower with a fluid dynamical approach.  A solar tower can be designed and constructed at a relatively low cost. However, the energy output tends to be small for its physical size compared to the ones of other renewable energy production systems. The technical improvement on this kind of generation system has been greatly decelerated since the termination of the operation of Spanish pilot plant in 1989. We have focused on tower part of the system to seek the enhancement on the power output of the turbine inside. As a result of our fluid dynamical shape optimization, a diffuser shaped tower is employed to increase the flow speed inside for a scaled model experiment.

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In this research, the energy balance of a vessel equipped with a wind-lens turbine (a high efficiency horizontal axis wind turbine with a diffuser) are investigated. The assumed vessel is the total length 180m width 30m width car carrier. Wind tunnel experiments are performed with 1/100 scale model, and the wind velocity distribution, the wind resistance and the power of the wind turbine is measured. In addition, the energy balance in the North Sea route connecting between St. Petersburg (Russia) and Sunderland (UK) is calculated by using the wind data. As a consequence, by coping effectively with a head-wind, it is shown to obtain a positive energy balance. Furthermore, by yawing parallel to the wind turbine, the energy balance is improved.

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Wind lens turbines with its unique brimmed diffuser, are spaced closely together to investigate their interference on power output. Three wind lens turbines in a triangle array normal to smooth flow at variable spacing are operated and maximum power output is measured in comparison with each turbine in a stand-alone setup. We observed several interesting phenomena, like power drop at close spacing and power rise with increased spacing compared to the stand-alone setup. Further, we observed wide fluctuations of individual turbine power and used flow visualization to find out the reasons.

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By using the output of high-resolution downscaling around Japan with long-term re-analysis data and a mesoscale meteorological model, the variability of the annual mean wind speed and the potential capacity factor have been evaluated. The results indicate that (1) the change in the annual average wind speed within one year may exceed 10%. (2) Although the relative value of the standard deviation of the annual average wind speed is about 2% or less in most areas, it tends to be large in areas where the average wind speed is high. (3) Although the trend of the annual mean wind speed is not significant in most land areas, it is significant along the coast of Hokkaido and the Tohoku district. (4) The standard deviations of the annual capacity factor suggest that the differences between the maximum and minimum annual energy production levels in 20 years reach 15%.

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In this study, numerical simulation for the load estimation on the support structures of wind turbine during operation was validated by measurement and the load characteristics of the support structure were investigated. Following results were obtained. The simulation shows good agreement with the measurement in terms of fore-aft tower base moment. The gain scheduling has to be modelled appropriately for the accurate estimation of fore-aft tower base moment. The fore-aft moment on the tower shows maximum value at rated wind speed at the base of the tower, while at the tower top, the maximum load is observed at the cut-out wind speed.

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Large eddy simulations of flow around an upwind horizontal axis wind turbine operating at low, optimal or high tip speed ratios were performed with an actuator disk model in order to investigate the effects of the tower on the wind velocity distribution in the wake of the wind turbine and the vertical distributions of the drag and lift coefficients of the tower. Results confirmed that the effects of the tower on the wind velocity distribution were significant and changed with tip-speed ratio. It was also confirmed that the drag coefficients of the tower changed drastically in the vertical direction around the lowest height of the rotor.

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Risk estimation of buildings due to strong wind disaster based on resistance strength and costs of each portion was described. By using risk estimation considering resistance strength and costs of buildings, resistance abilities against strong wind can be compared with those of other buildings. Furthermore, most weakest member against strong wind can be known correctly. Risk estimation procedure concerning strong wind disaster was provided in this paper. The provided risk estimation was applied to 2 cases of real buildings, and verification of this risk estimation was investigated.

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Many studies on flying of a piece of wind-borne debris are based on the assumption that its mass distribution is non-eccentric. This report focused on the mass eccentricity of plate-like debris, and the effects of the eccentricity on the distance, angle and speed of flying were investigated using a wind tunnel test and a numerical calculation. The numerical results corresponded well to the experimental results. By parametric studies on the eccentricity and initial angle of plate, it was found the eccentricity of plates had a strong impact to its flying distance under strong winds. Especially, the flying distances of plates with eccentricity of 8% to 18% are much bigger than those of non-eccentricity plates.

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How a tornado in Tsukuba City in 2012 attacked a severely-damaged house was investigated. It was indicated that the differences of estimated damage wind speed based on a steady wind flow in some reports were mainly caused by the difference of wind force coefficients and weight assigned to the damaged house. In this paper, by chasing the moment in a time evolution while approaching of tornado based on Rankine's model considering a sudden drop in atmospheric pressure as well as wind force due to a horizontal wind, the overturning wind speed was decided. It was found that a sudden drop of atmospheric pressure caused by a rapidly-moving tornado reduced the damage wind speed. 

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This paper illustrates the way to develop wind-induced damage rate function for timber residences for the purpose of application to general areas. In order to explicitly consider the strength of residential components, statistical values obtained by past load tests were applied to the corresponding fragility functions. Since it is generally considered terrain situation has influence on instantaneous wind velocity and resultant wind-induced damage, new factors representing the influence were introduced in the damage rate function, which were obtained by CFD analysis. The developed function was verified by comparing with past actual damage rate.

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Statistical features of waterspouts in Japan were investigated based on the tornado data base during 23 years from 1991 to 2013. Because a large number of waterspouts were reported after 2007, the tornado probability of each prefecture was different from that of the previous studies. The tornado probability exceeded 5 tornadoes/10000km²/year in 7 prefectures and 0.2 tornadoes/10⁶person/year in 9 prefectures, respectively. Tottori prefecture is the highest values of the tornado probability in Honshu island, considering the waterspouts during 2007 to 2013. It is important to make clear the generation point, the vortex structure, the organization mechanism and the frequency of the waterspouts around the Japan coastal region.

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In the present paper, we introduce two kinds of computer vision technique what enable to decide the location and position of tornado in three-dimensional space coordinates. One is a trial-and-error method and another is an epipolar constraint method. Both two techniques estimate the three-dimensional outline of tornado from two pictures of funnel cloud taken from the different points. The estimated results for Tsukuba tornado almost agreed with the data of the Doppler radar in MRI. We expect that these techniques improve the accuracy of the photogrammetric method evaluating the maximum tangential velocity and radius of a tornado vortex from funnel cloud pictures developed by us.

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 This study deals with the optimal time interval over which instantaneous wind speed obtained as crude output from an anemometer is averaged to be applied for regulations of train operation under strong winds. First, we compared the measured values of aerodynamic force which exerts on a full-scale train car model under natural winds with the estimated values of aerodynamic force from the measured natural wind speed and the aerodynamic force coefficient. As a result, it was found that 3 sec is the appropriate averaging time to estimate peak values of aerodynamic force which exerts on train car body. Second, we evaluated quantities of safety and stability of train operation with loss function we defined. As a result, it was found that both losses of safety and stability in averaging times of 3 or 4 sec of the instantaneous wind speed are smaller than those in the standard condition in spatial average of 3 instantaneous wind speeds.

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Severe wind hazard occurred on coastal area in Kochi Prefecture on 10 December 2013. The present study aims to clarify the meteorological environment of this event and the characteristics of wind gust. The wind hazard was caused by the passage of intense rain band when the extratropical cyclone developing rapidly passed above the damaged area. We found that the damaged areas in Konan city were yielded by more than two tornadoes. Their intensities are F0 for the wide tornado and F1 for the narrow tornado, respectively. The other damaged areas are scattered. These damages were caused by strong westerly wind gust accompanied by intense rain band and southern wind toward depression.

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The purpose of this paper is to promote tornado disaster countermeasures for local governments. The actions that local governments have to take after a tornado disaster are arranged. These results are based on the interview given to the officials of the local government that received a tornado disaster, and are classified into four categories based on the disaster phases; that is, prevention, mitigation and preparedness, emergency response, and recovery and rehabilitation. Furthermore, the results are compared with the tornado countermeasures specified in the Saga City Local Disaster Management Plan. It is hoped to specify tornado disaster countermeasures in the Local Disaster Management Plan of the other local governments.

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This paper discusses the asymmetric flow around a circular cylinder in the critical Reynolds number region by using LES. First, asymmetric time-averaged flow and pressure distributions are numerically investigated. Especially the balance of the volumetric flow in the asymmetric state is focused on. Next, unsteady flow characteristics around a circular cylinder in the critical Re region are discussed. Consequently, it is clarified the asymmetric flow is brought about by the interaction of the flows between on one bubble side and on the other one.

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The wake galloping appears when  two cylinders are placed close together and the cable vibrates mainly in the vertical direction. The wake-induced flutter is known as a coupled vibration in both vertical and horizontal directions and occurs when the distance between the both cables is far and they are in staggered
arrangement. A series of wind tunnel tests for two parallel cable models with different arrangements have been carried out. Then, it becomes clear the coupling terms which is phase with the displacement of unsteady aerodynamic forces must play vital roles to the wake-induced flutter.

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In 2009, the Ikitsuki-ohashi Bridge, a truss bridge in Nagasaki Prefecture with a central span length of 400 m, was discovered to have a crack in the bracing member of the bridge. As a result of the subsequent vibration measurement at the site, the main cause of the crack was identified as Kármán vortex excitation. However, excitations were also observed in the wind velocity range of 7-8 m/s, which was lower than the resonance wind velocity of the Kármán vortex excitation. Conventionally, according to the results from a wind-tunnel test using a side ratio of B/D=2-8, the motion-induced excitation was confirmed. However, the side ratio of the section of the bracing member is B/D=1.18, and the motion-induced excitation in the case of this side ratio has not yet to be confirmed by the conventional wind-tunnel test. Therefore, in this research, a spring supported test was carried out targeting a rectangular cross section of B/D=1.18. Furthermore, unsteady aerodynamic force measurement and flow visualization were performed and the results of the spring supported test were discussed. In order to clarify the relationship between the generation of motion-induced vortex and the side ratio of B/D, flow visualization was conducted by changing a side ratio of B/D from 0.5 to 2.0.

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Aerodynamic force acting on an oscillating body in turbulent flow consists of three components; force due to self-induced turbulence, gust force caused by oncoming turbulent flow, and movement-induced force caused by body movement (the “mov” component). In the flutter analysis in turbulent flow, these three components are often treated as the united force without decomposition into each component. This research extracts the “mov” component from the entire aerodynamic force, and compares aerodynamic derivatives of the extracted “mov” component with those of the entire aerodynamic force. In the result, since there are not so much differences between them, it turns out that the conventional evaluation method using the entire aerodynamic force is sufficiently effective to describe the effect of “mov” component which results from the oscillation of a structure itself. In addition, it is shown that the spanwise spatial correlation of the aerodynamic force in turbulent flow decrease, though it is regarded as the perfect correlation.

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In this study, characteristics of fluctuating lift and spatial correlation for cylinder were experimentally investigated by wind tunnel testing. For rectangular cylinder, drag coefficient was almost constant, but fluctuating lift changed with wind speed. The total fluctuating force was between linear summation and square summation of both fluctuating lift forces at supports. In higher wind speed region, fluctuating lift forces at support was fully correlated to each other. Rectangular cylinder with spanwise varying section was employed to reduce fluctuating lift. Openings were more effective rather than appendages. Evaluation method of windward correlation length was also proposed.

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Most previous papers have reported the overshoot phenomena of wind pressure on a roof body under a condition where a gust attacks in a short-rise-time from a calm condition. This paper describes properties of unsteady wind pressures on a gable roof when a gust attacks in a short-rise-time from a steady wind condition according to experiments using a gust wind tunnel test. It was confirmed that overshoot wind pressure decreases with an increase in the initial wind speed, and the overshoot phenomena of wind pressure can be described by non-dimensional coefficients defined for example by the rise-time of a gust, wind speed or its acceleration.

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To investigate the effects of roof pitch on unsteady wind pressure around a gable roof structure, we measured unsteady wind pressures on gable roof bodies with several roof pitches subjected to a step-function-like gust using a specially-equipped wind tunnel. The results showed an overshoot wind pressure coefficient, which was a peak wind pressure coefficient while developing of overshoot phenomenon, was much bigger than that in a steady flow, and the overshoot wind pressure coefficient increased with a decrease in a non-dimensional rise time. It was found that the rate of increase depended on the measurement position and was strongly affected by the pitch of gable roof.

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In this study, the coefficients of peak wind forces acting on photo-voltaic (PV) panels on flat roofs of a 5-story medium-rise residential building and a 10-story high-rise building are investigated by wind tunnel tests. The following results are obtained; (1) Positive and negative large peak wind force coefficients occur on PV panels near area of the roof edges and around area of the penthouses, (2) For the wind direction where large negative pressures act on the lower side of a PV panel, a maximum positive wind force acts on it, and for the wind direction where large negative pressures act on the upper side of a PV panel, a maximum negative force acts on it. (3) Provided that PV panels are supported at 4 corners, the wind force coefficients of supports at corners have loading effect which are 1.3 ~1.5 times panel wind force coefficients for PV panels at roof edges.

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The effects of wind direction on generation points of unsteady vortices and unsteady wind pressure on a gable roof body under a short-rise-time gust were investigated using a computational fluid dynamics (CFD) simulation with an LES model. The unsteady wind pressure at some points on the body subjected to the gust was compared with the results of wind tunnel tests, and it was confirmed that the overshoot phenomenon of wind pressure occurred in the CFD simulations as well as wind tunnel tests. It was found that an unsteady vortex, which was generated on the surface of the gable body, caused the overshoot phenomenon of wind pressure. The generation points of unsteady vortices changed with wind direction. The overshoot of wind pressure on the roof face and the gable wall face was considerably large in the case of wind directions of 45 degrees and 15 degrees, respectively.

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The characteristics of peak external wind pressures acting on walls of low-rise building were examined by using wind tunnel test results performed on models with various roof slopes and eave heights. On one hand, pressure distribution of positive wind pressure is found to be relatively uniform; and hence zoning seems unnecessary. On the other hand, large suctions are observed at the lateral edges of walls, which results in the necessity of zoning. Strong non-Gaussian characteristics are found not only for negative wind pressures but also for positive wind pressures and the probability density does not necessarily become Gaussian when aggregated loads are considered. Comparisons with the specified values in the AIJ Recommendations for Loads and Buildings in Japan were also performed. 

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Wind force coefficients on a semi-open type structure are proposed on the basis of the result of a wind tunnel experiment. Two cases of gable-wall opening are investigated; only one gable wall is open in a case, while both gable walls are open in other case. Closed-type model is also tested for a comparative purpose. The wind pressures are measured both on the external and internal surfaces in a turbulent boundary layer. Based on the results, we propose the structural wind force coefficients for the main wind force resisting system using the LRC method, in while focus is on the bending moment involved in the columns as the load effect. 

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The negative peak pressures on a roof of a low-rise residence are estimated using two models of probability density functions in this study.  Both methods apply Hermite polynomial function approximated by finite series to translate a process to non-Gaussian process.  One is a method which translates Gaussian process to non-Gaussian process as shown in literatures (HP model).  The other translates Mixture Gaussian model to non-Gaussian process (Mixture model). There is a restriction on the relationship between skewness and kurtosis to apply HP model and the accuracy of estimating negative peak pressure is deteriorated when the statistics are deviate from the relationship.  It is clarified that Mixture model relaxes the restriction and improves the estimation of peak values.

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Solar power plant on roofs is attracting attention in recent years. In fact, there are gradually increasing numbers of such efforts. In such a case, the attention should be drawn to the wind loads for not only the photovoltaic panels mounted on a roof but also the roof itself. The net wind loads acting on the roof fastener may exceed the design wind loads for the roof without PV panels. This paper investigates the peak wind force coefficients of panels mounted on roofs. The minimum wind force coefficients of the PV panels have almost the same value in various panel layouts. Since the wind loads acting on the roof under PV panels are larger than the wind loads which are generally used by designers, it is necessary to consider the severe wind forces for all over the roof as same as the edge area of the roof.

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Solar power generation has been expanding as one of the non-fossil fuel energy systems in recent years. The weight of photovoltaic arrays is very light therefore wind load is the dominant load for this kind of structure. Generally wind resistant design is performed according to JIS C 8955. However outside the scope of JIS is the tilt angle of 10 degrees which is favorable in terms of efficiency, so a number of studies have been carried out on the wind forces acting on photovoltaic arrays. Most of these studies are based on wind tunnel experiments or computational fluid dynamics. These methods are available to estimate the wind loads comprehensively. However it is important to verify the results with these methods by comparing with the phenomenon in the fields. Therefore this paper shows the characteristics of wind forces acting on a photovoltaic array in field measurements. This data shows that there is good correlation with the results of wind tunnel experiments. The data also shows the wind pressure fields in typical cases.

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This study investigates the influence of middle-rise urban block area for the wind pressure prediction of target high-rise building using large-eddy simulations (LES). Four LES cases were carried out and compared with four wind tunnel experiments, respectively. No obstacle case shows that the same recovery characteristics of vertical velocity profile with the wind tunnel experiment, furthermore the nesting grid doesn't affect the velocity spectrum largely. Urban block and no-target building case shows that the vertical profiles of velocity and turbulent intensity near the ground is good correspond with the wind tunnel experiment because of the flow development through the urban block. No-urban block and target building case shows good correspondence with the wind tunnel experiment for the wind pressure coefficients of average, standard deviation, max-peak and minimum-peak. Urban block and target building case also shows good correspondence with the wind tunnel experiment.

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To investigate the aerodynamic characteristics of the concentrated photovoltaic system (CPV) of “twodivided-panel type” constructed on the ground, we conduct an experiment in a wind tunnel, using a scale model for a wide range of attack (ϕ) and yaw (θ) angle. Since the acceptance side of the conventional type of CPVs always faces upside in the night, the accumulated sands or dusts on it impede power generation. For the CPV of two-divided-panel type, the panels can be rotated upside down, so that the acceptanceside is kept relatively clean. Attention is focused on the effect of the slit between the two panels.

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This paper discusses the availability of LES on the wind-resistant design for buildings in cities. In order to predict the wind pressures and forces on actual complicated-shaped buildings with good accuracy, we introduce the unstructured-grid system which is formulated on the open source CFD code. Especially the hybrid method is employed consisting of the Cartesian grid for the accurate turbulence structures in the urban canopy, and the unstructured-grid for the accurate wake flows around the specified building inside the densely arrayed buildings in the center of cities. In this study, we apply this method to the wind load estimation of a high rise building in a city at inclined wind direction to the main streets. The obtained results of wind pressure distributions on the surfaces of high-rise building are estimated in comparison with the previous experimental data.

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