Isaac Lun

City University of Hong Kong | CityU · Department of Architecture and Civil Engineering

It is still difficult to confirm from available data if global warming and climate changes have played a role in increasing heat-related injuries. However, it is certain that global warming can increase the frequency and intensity of heat waves, which can cause discomfort to the human body and, in the worst case, can lead to more heat illness casua...

The paper provides an overview of energy shortage in the context of demand and supply of energy in the context of Japan after Fukushima incident. In line with the rapid urbanization, the demand of electricity is increasing, especially in building sector. It is thus deemed important to peruse the current status of available energy sources for genera...

The current status and remaining issues of coupling CWE models with mesoscale meteorological models (MMM) are reviewed from the viewpoint of computational wind engineers. By way of three examples to demonstrate the typical application areas where the coupling approaches are needed, the governing equations considered, and the difficulties to couple...

High-performance insulation, draught stripping and double glazing have effectively sealed off the fresh air routes and have made adequate natural ventilation impossible inside the modern energy-efficient home nowadays. Cross ventilation, a passive cooling method for buildings, is a major type of natural ventilation. Various study approaches have be...

Urbanization is progressing rapidly in many Asian cities. The process of urbanization has modified the land use from natural environment into built environment. It alters not only the surface energy balance of the urban canopy, but also brings about a great quantity of anthropogenic sources of waste heat through air-conditioning, cars, etc. In addi...

This paper reviews the recent developments in CWE research for predicting the pedestrian level wind and thermal environments in urban areas, primarily achieved by the researchers in the field of environmental engineering in Japan. First the progress in turbulence models in the last decade and in their applications to the problems related to wind cl...

Urbanisation is progressing rapidly in many Asian cities. The process of urbanisation has modified the land use from natural environment into built environment. It alters surface heat balance by changing sensible and latent heat fluxes, heat capacity, surface albedo and together with the use of fossil fuels, brings about a great quantity of anthrop...

Accurate prediction of the wind energy distribution over terrains is essential for the appropriate selection of a suitable site for a wind power plant. This paper presents two-dimensional numerical simulations of flow over three common types of topographic features, i.e., a hill and two types of slopes (up-slope and down-slope). In a previous inves...

The purposes of this investigation are to look into the actual conditions of urban residential indoor environment in China during the winter season, and to discuss the thermal comfort as well as to understand the possibility of space heating energy conservation. Investigations of indoor thermal environment were carried out in Harbin, Beijing, Xi’an...

The accurate prediction of the wind energy distribution over terrains is important for making an appropriate selection of a suitable site for installing wind power plant. In this study, two-dimensional numerical simulations of flow over two common types of topographic features, i.e. a cliff and a hill, are presented. Three types of turbulence model...

The accurate prediction of the wind energy distribution over terrains is important for making an appropriate selection of a suitable site for installing wind power plant. In this study, two-dimensional numerical simulations of flow over two common types of topographic features, i.e. a cliff and a hill, are presented. Three types of turbulence model...

The purpose of this survey is to know the actual conditions during the summer of the residential indoor environment in urban area in China. The apartment houses under investigation were sited in urban area of Shanghai, Hong Kong and Xi'an. The questionnaire survey and the measurement of indoor temperature and humidity were done in the summer of 199...

The purpose of this survey is to look into the actual conditions of the residential indoor environment in urban areas in China during the summer for discussing thermal comfort and the possibility of space cooling energy conservation. The apartments under investigation were located in Shanghai, Hong Kong and Xi'an. The questionnaire survey and the m...

The two parameters of a Weibull density distribution function were calculated for three different locations; a city area, an extremely exposed area in a city centre and an open sea area in Hong Kong. A long-term data source, consisting of thirty years (1968–1997) of hourly mean wind data, was adopted and analysed. Based on these data, it was found...

The 30-year long-term (1968–97) wind speeds were analysed, and along-term hourly wind speed database developed. Based on the statistical analysis, the outdoor design wind speeds at different significant levels (0.1%-10%) were determined for the summer and winter periods in Hong Kong. It was found that, at the 2.5% significant level, the summer and...

A series of wind-tunnel tests on a NACA 0012 airfoil was conducted to simulate the aerodynamic effects of runback ice. The drag and lift effects on the airfoil were assessed using wind-tunnel balance For three geometries of triangular section ice shapes at three different chordal positions, The results show a great degree of sensitivity of the aero...

Two-phase flows are encountered in a wide range of industrial and natural situations. Due to their complexity such flows have been investigated only analytically and experimentally. New computing facilities provide the flexibility to construct computational models that are easily adapted to a wide variety of physical conditions without constructing...

A two-dimensional numerical simulation of airflow around bluff bodies is presented in this study. The two turbulence models, i.e., standard k- ε model and RNG k-ε model, are employed to predict the flowfield and wind effects on bluff bodies. The results of the study highlight and compare the discrepancies between these two turbulence models in capt...