Investigations of Boundary Layer Wind Characteristics in Typhoons for Structural Design and Wind Engineering Application

Project: Research

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Description

Typhoons are one of the world’s most destructive natural disasters. Hong Kong andGuangdong are located in one of the regions most seriously affected by typhoons. Thus,understanding the boundary layer wind structure of typhoons and investigating their windcharacteristics are vital to disaster mitigation and structural design in typhoon-prone areas. Thisproject aims to obtain reliable and valuable wind data from a variety of sources to investigate thewind characteristics within the atmospheric boundary layer (ABL) during typhoons for use instructural design and wind engineering application. The first source for these data will be thenumerous anemometers that have been installed at various heights in over 40 establishedmeteorological observation towers in Guangdong and at 51 weather stations in Hong Kong.Meanwhile, a number of remote sensing profiler systems such as Doppler radars and sodarslocated in the coastal regions and inland areas of Hong Kong and Guangdong will be used tocapture wind data within the ABL during the passage of typhoons. Additionally, the adoption of amobile facility that includes a vehicular Doppler radar and three portable meteorological towerswith wind monitoring systems will enable the measurement of wind data and speed profiles at orclose to typhoon landfall locations. This is expected to provide valuable information on theboundary layer wind structure in the eye-wall regions of typhoons. The wind data will besimultaneously measured from various heights (from surface level up to 1,500 m) at numerousmeasurement sites during typhoons. Vertical profiles of mean and gust wind speeds andatmospheric turbulence properties will be obtained based on the wind data measurements. Theresults of the proposed simultaneous observation program and intensive data analysis willprovide useful information regarding the structure of typhoons over varied terrains andcorresponding to the various stages of the typhoon life cycle. Wind tunnel tests will be performedto study boundary-layer flow fields over topography and the effects of the scaling of topographicalmodels. The field measurements will be used to verify the accuracy of the wind tunnel test results.The combined field and model test study will enable a thorough assessment of the effects ofterrain roughness and topography on boundary layer wind speeds and turbulence properties toclarify the appropriate model scale range that will provide credible results. Finally, thesubsequent analysis results of the measurements will be used to evaluate the adequacy of thecurrent codes of practice and to apply that knowledge to structural design in typhoon-proneregions.The proposed comprehensive field measurements of wind speeds and atmospheric turbulencecharacteristics at various sites during typhoons will provide a fundamental improvement ofknowledge in boundary layer wind structure, wind climate, typhoon wind characteristics, windfield modeling and design wind loads for Hong Kong, Guangdong and the surrounding regions.Furthermore, the monitoring results will provide essential information for the verification of windtunnel testing techniques and for the development of structural design codes or standards. Thefindings of this study will also be invaluable to policy makers in developing typhoon disastermitigation regulations and implementing mitigation strategies. The output of this project isexpected to be of importance to the wind-resistant design of buildings and structures not only inHong Kong and mainland China, but also in other global regions in which typhoons and tropicalstorm winds control the design parameters.

Detail(s)

Project number9041899
Grant typeGRF
StatusFinished
Effective start/end date1/01/1426/03/19