Wind Engineers, JAWE
Online ISSN : 1883-8413
Print ISSN : 0912-1935
ISSN-L : 0912-1935
Volume 1996 , Issue 67
Showing 1-15 articles out of 15 articles from the selected issue
  • Jun Kanda
    1996 Volume 1996 Issue 67 Pages 1-4
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    Various aspects are pointed out for problems related to full scale wind measurements. At first by considering the difference between meteorology and structural engineering, the accuracy of evaluation should be investigated from view points of applications. Engineering approach in meteorology and verification by full scale measurements in structural engineering are both equally important. Clarification of purposes for observations are also important to develop anemometers of wind observation systems. Long-term observations and data-base developments are necessary for the future of wind engineering and application of GIS may also be expected in this field
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  • Gennichi Naito
    1996 Volume 1996 Issue 67 Pages 5-8
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    Recent wind observations are discussed in the science and engineering aspects. Meteorology or atmospheric science usually studios about ten times larger temporal and spatial behaviours of wind than those as the engineering subject. Various wind sensors are introduced for observation of lower atmosphere below about 1 km. Engineering projects are also shown concerning wind observation.
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  • Teruhisa AMANO, Takeshi OHKUMA, Akihisa KAWAGUCHI, Satoru GOTO
    1996 Volume 1996 Issue 67 Pages 9-14
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    The wind structure of the atomosphenc boundary layer has recently become a vigorous concern in wind-resistent design of high-rise buildings. This study deals with the observation in Ckinawa by Doppler sodas during two typhoons in 1995. The mean wind speeds have shown good agreements with the referenced data obtained by the ultrasonic anemometer. It is confirmed through the analysis of three hours' record for each typhoon that the wind profiles are basically fitted by power law with the exponent of about 0.3. The height of the gradient wind, however, changes successively from 200 to 550m due to the Influence of the layers of clouds. The intensities of u-and v-component of turbulence have shown larger values than the ones by anemometer, while the intensity of the vertical component well coincides with the anemometer.
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  • Fumiaki KOBAYASHI
    1996 Volume 1996 Issue 67 Pages 15-20
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    The spatial distribution of strong winds accompanied by weather disturbances, such as a typhoon. an extratropicat cyclone, a winter monsoon wind and a downburst were observed using a Doppler seder. The charac-teristics of gusts caused by severe storms were quite difference in each case. Especially. gusts were generated by mesoscale cloud systems including in the large scale dynamicalwinds. in thecase of wet type weather disturbances. Data number ratio in the functions of horizontal wind speed and height was also discussed.
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  • Yukio TAMURA, Yoshiharu IWATANI, Atsushi SASAKI, Ken-ichi SUDA, Kunio ...
    1996 Volume 1996 Issue 67 Pages 21-28
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    Authors' group has been conducting the full-scale measurement of atmospheric boundary layer wind speeds by Doppler Sodar at two sites. One is located at the seaside, and the other is in a residential zone of suburban area. Wind speeds are measured at various heights ranging from 40m to 500m above the ground. In this paper, the quality of the data obtained in various different measuring conditions and the meaning of the data are discussed.
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  • Tokunosuke FUJITANI
    1996 Volume 1996 Issue 67 Pages 29-32
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    In the present paper wind observation was discussed in view of meteorological services in Japan. The main purpose of the wind observations at meteorological observatories is to collect data for numerical weather prediction use as initial values. Collected data arc processed by quality checks, initialization and 4-dimensional assimilation technique, and then converted to 3-dimensional grid point values. In spite of some concerns of representativity of the meteorological stations, therefore the present surface observational system is suitable for collecting these data.
    For calculating design wind speed by using wind data collected at meteorological stations we should adopt some correction techniques for evaluating effects of changes of anemometers and observational conditions. For this purpose wind tunnel test and numerical simulation techniques will be considered.
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  • Yoshiki ITO, Tsuyoshi NAGANUMA, Ryou KODAMA, Tatsuo HANAFUSA, Junji SA ...
    1996 Volume 1996 Issue 67 Pages 33-38
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    Doppler sodars have been widely used to measure the wind profiles up to several hundred meters. The comparisons with tower instruments show that the Doppler sodars offer the reliable estimations of the mean wind speed (U) and direction (D). From the comparison experiments held at Meteorological Research Institute (MRI), the correlation coefficients are better than 0.9 for U and D, and the rms differences are 0.7-2 mis and 10-25 deg for U and D respectively. An evaluation of the standard deviation of the vertical wind (σDw) is somewhat difficult, but we have the correlation coefficients better than 0.8 and the rms differences of 0.15-0.2 m/s forσDw. Theheavy precipitation and/or the strong wind reduce the maximum detectable height and degrade the accuracy of the wind measurements.
    Measurement errors, which seem to be caused by the beam deflection due to refractive changes in the acoustic propagation, prevent the accurate observation of instantaneous horizontal wind velocities. Though thdeviation of the horizontal wind (σDu) can be deduced by the simplified method using the tilted beam axis components, the five-beam phased array Doppler sodar has the capability to measureσu andσv.
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  • Hidetoshi HAYASHIDA, Syoichiro FUKAO, Takahisa KOBAYASHI, Hiroshi NIRA ...
    1996 Volume 1996 Issue 67 Pages 39-42
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    Recently, with an increase in the number of high-rise buildings, information about wind velocity at high altitudes has become more important. Boundary layer radar observations were carried out for about three months following completion of improvements in the observation system at the Meteorological Research Institute in Tsukuba. This paper shows the vertical profiles of wind velocity and a comparison with the results of wind profiler and high-rise tower observations, The results indicate that boundary layer radar can observe wind velocity up to an altitude of two to three kilometers and is of great use as a device for collecting wind data at high altitudes.
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  • Shaw NISHINOMIYA
    1996 Volume 1996 Issue 67 Pages 43-46
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
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  • J. MAEDA, S. TAKAKI, S. YAMAGATA, N. ISHIDA, T. YOSHIMURA, N. TOMONOBU ...
    1996 Volume 1996 Issue 67 Pages 47-54
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    Some effects of topography on properties of strong wind distributions are discussed using results of a few recent observation results by the authors group.The observation sites include a seaside, the top of a mountain and a wide area network system which consists of 120 measurement sites each covering a 20 square kilometers area within Kyushu island. The measurement data include three components of wind speed, wind profiles and wind distribution in strong winds.
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  • Osamu NAKAMURA, Shigeo AOKI, Takeshi OHKUMA, Koichi MIYASHITA
    1996 Volume 1996 Issue 67 Pages 55-60
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    Field measurements of winds on atmospheric corrosion for two important cultural properties were carried out.
    First, observations of a Buddhist statue were made. In the area where the statue is located, winds blow from the south or north most frequently. On rainy days, winds blow mostly from the north and during strong winds, winds are in most eases from the south. Due to this, it was presumed that northerly winds would cause pollutants and that southerly winds would bring salt particles from the sea to the Buddhist statue.
    Second, observations were made of a shrine as another important cultural property. Metallic parts of the shrine building corrode due to damage from salt. Although an analysis which is directly related to atmospheric corrosion has yet to he carried out, it was found that strong winds blow mainly from the sea in this area. Furthermore, the wind direction characteristics caused by the topographic features along the Sea of Japan in Shimane Prefecture were investigated by carrying out analyses of winds which include data obtained at several meteorological offices.
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  • Tohru SAITO
    1996 Volume 1996 Issue 67 Pages 61-66
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    When discussing the aerodynamic stability of a structure, in-depth knowledge of characteristics of wind prevailing at the site where the structure is to be erected constitutes an engineering input of vital importance to adding substance to the discussion.
    In other words, the construction site wind condition varies with locations from the effects of surrounding topographical features. Therefore, even the structeres of indentical design, when constructed in different locations, demand different engineering considerations as regards the wind resistance capability or vibration control measurs.In addition, take onestructure and the exposureto wind is not necessarily uniform over its entire surfaces. Also, the wind effects can totally differ depending on the wind direction.
    This paper reviews a series of studies conducted by the authors on the effect of topography on natural wind and consequent structure responses to wind excitation focusing on some particular types of structure chosen as typical examples. The characteristics of winds of winds blowing over the hill top.small islands, or through the channel or strait, were examined and the effects of natural winds deflected by these topographical features on the structures analyzed by such wind effects prediction techniquse as the observational survey, relief map wind tunnel testing, computerized tecnique of computational fluid dynamcs (CFD), etc.
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  • C omparison between wind tunnel experiment and field observation
    Makiko KATO
    1996 Volume 1996 Issue 67 Pages 67-70
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
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  • Akashi MOCHIDA, Shuzo MURAKAMI, Sangjin KIM
    1996 Volume 1996 Issue 67 Pages 71-78
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    The results of CFD analyses of flow over the Kanto plane were presented in this paper. Here, the model for geophysical flow problems developed by Mellor and Yamada was used for turbulence modelling. The diurnal variation of the flowfield was predicted imposing the typical meteorological conditions at the end of July as boundary conditions. The results of predictions were compared with measured data. The effects of the change in land-use conditions caused by urbanization on the local climate were discussed by examining the energy budget at the ground surface.
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  • Tetsuro TAMURA
    1996 Volume 1996 Issue 67 Pages 79-84
    Published: April 30, 1996
    Released: September 28, 2010
    JOURNALS FREE ACCESS
    The techniques of numerical simulation are expected for the prediction of wind flows over various kinds of complex terrain. However the optimum method for use of this technique has not been established to this day. Here the basic concept, scope and status of the numerical prediction of the wind flows over the terrain are investigated. In order to clarify the effects of the undulation and the roughness of the ground surface on the wind characteristics such as the vertical profile of the time-averaged and the fluctuating wind velocities, from an engineering point of view it is proposed how to simulate the wind flows over various terrains. Finally I show some numerical examples for an actual complex terrain model as well as a single basic model like a hill.
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