Investigation of Tropical Cyclone Wind Characteristics and the Effects of Extreme Winds on Super-tall Buildings 

Project: Research

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Description

Tropical cyclones (TCs) can result in extremely destructive natural disasters. The effective prevention and reduction of TC-induced disasters requires extensive knowledge of TCs. However, previous observations of TC winds were mainly conducted within a very shallow range of their depth. In particular, reliable observations of TCs over land, which are required for the design of high-rise structures, are still lacking, and very few if any height-resolving models for TC pressure fields and wind fields are available for risk assessment. Exploring the wind characteristics and structural features of TCs throughout their entire depth, and improving the current TC wind field models, is therefore necessary. Hong Kong is located in a TC-prone area, and more than 50 meteorological stations have been established for long-term observations of various weather elements. The equipped instruments include airborne GPS-dropsondes, radiosonde balloons, Doppler Radar/Sodar/Lidar profilers, numerous anemometers on masts, offshore platforms, and buoys. The archived long-term observation records from these instruments provide an excellent and even unique data platform for the investigation of wind characteristics of TCs over various terrain conditions. The aim of this project is to present a comprehensive investigation of the wind characteristics of TCs and the effects of extreme winds on super-tall buildings in Hong Kong, and will consist of four consecutive tasks: (1) an observational study of TC structures and wind fields within the entire TC depth; (2) modeling of the TC spatial pressure and wind fields below the TC outflow layer; (3) establishing the vertical profiles of TC-dominated design wind speeds; and (4) assessing TCinduced wind effects on super-tall buildings. Task 1 will be conducted on the basis of over 20- years’ of observation records from various types of measurement instruments in Hong Kong. TC thermodynamic and kinematic structures, along with wind field characteristics over the entire TC depth, will be investigated through both case study and composite analysis. Vertical profiles of wind speed and direction, atmospheric pressure, temperature, and relative humidity within the whole TC depth will be presented and discussed as a function of storm-relative position, TC strength, terrain condition, and other environmental aspects. In Task 2, a height-resolving TC pressure field model will first be constructed by combining the observed vertical profiles and a radial model. The model will then be applied in conjunction with a TC wind field model to establish a refined 3-D TC wind field model. The established model will take into account the outward tilting feature of the radius of maximum wind (RMW) and the vertical variation of the horizontal eddy viscosity. This model will be able to replicate the low-level jet (LLJ) feature of TC wind profiles and its dependence on radial position. Tasks 3 and 4 will focus on two important issues in wind engineering practices. First, vertical profiles of TC-dominated design wind speeds with different return periods in Hong Kong will be established using the Monte Carlo simulation techniques and the newly proposed 3D wind field model. Next, full-scale measurements of the wind effects on two super-tall buildings will be conducted during TCs to assess TC-induced wind effects on skyscrapers. Wind tunnel tests with realistic TC wind fields (e.g., LLJ feature, veering wind, profiles of TC winds) will then be conducted on both rigid and aeroelastic models of the two buildings. The experimental results will be further compared with the field measurements to evaluate the applicability and accuracy of different model test techniques in estimating the wind effects on high-rise buildings during TCs. The objective of the proposed project is to enhance our understanding of TC structures and wind characteristics, and thus develop a new (3D) wind field model and improve the wind-resistant design of super-tall buildings in TC-prone regions and verify wind tunnel experimental techniques.  

Detail(s)

Project number9042770
Grant typeGRF
StatusActive
Effective start/end date1/09/19 → …