A modified k-e model that restricts turbulent time scale using Durbin’s limiter was applied for numerical prediction of wind pressure distributions of building models. It is known that the standard k-e model tends to overestimate wind pressure of windward

We consider the overnight evolution of an initial two-layer thermal stratification (a warmupper layer and a cooler lower layer) in an enclosure ventilated via openings at high and low levels.Results of our laboratory experiments show that an efficient displacement flow is not always established and four distinct ventilation flow regimes are observed depending on the ratio R (= at /ab ) of the upper opening area, at , and lower opening area, ab ( > 0). For a given initial stratification, displacement flow is established only if R is sufficiently small (i.e. at

We investigate two different natural ventilation regimes of an auditorium or other occupied open-plan space which is equipped with pre-cooling. The room has a low-level vent and a high level vent. The occupants act as a source of heat, which if without pre-cooling, can lead to the room becoming too warm for comfort. In the first ventilation regime, a chiller is fitted to the low-level vent, and the occupants provide positive buoyancy which drives the ventilation upwards and draws fresh air through the pre-cooling system.

In order to clarify whether a combination of designs is optimal, design elements are divided intodesign variables and random variables in the inquiry process for the optimal design. Design variablesrelated to the model are selected by a genetic algorithm, and random variables related to outdoor condition are selected by the moment method. The whole process of optimization consisted of a two-step procedure to reduce the calculation loads for finding the optimal solution. This study carried out a simple analysis using a coarse mesh considering the calculation loads in the first step.

We describe the results of simple modelling and some laboratory experiments of the natural ventilation flows which can develop in an office building when air is supplied from a central atrium, passes through the floor-space of the building, and then vents through stacks at the perimeter of the building.

Evaluating naturally ventilated buildings for performance is a difficult task, often relying oncomputer simulations and modeling to assess thermal comfort and airflow issues. This paper presents the long and short term monitoring procedures and data devised to determine the overall building performance of a naturally ventilated office building in the United Kingdom.

Predicting the performance of natural ventilation is difficult, especially for the large scale naturally ventilated buildings, because of the lack of accurate and efficient prediction tools. This paper presents a strategy, integrating a multi-zone model and computational fluid dynamics (CFD), to improve natural ventilation prediction and design. Large openings and atrium are broadly used in naturally ventilated buildings to promote buoyancy force and optimize air movement. How to properly deal with large openings and atrium is discussed and compared in this paper.

Natural ventilation is a more pleasant and acceptable ventilation mode, which is favorable to human physical and psychological comfort and health. In this research, experiments and analysis on the fluctuant characteristics of natural wind in outdoor environment and in different positions of indoor area are conducted. The authors analyze the physical structure of airflow fluctuations with turbulence statistical theory, chaos and fractal theory. The fluctuant characteristics of the natural wind in different built environment are found and generalized in the paper.

When designing natural ventilation for complex buildings, it is key to understand whether there is a unique solution for the flow, or if multiple flow regimes are possible. Here, we show that in a 2 storey open plan office type building, in which the floors are connected to a common atrium, two stable flow regimes may occur under identical conditions.

The aiflows driven by a revolving door that links two rooms of initially uniform temperature are examined. Two situations are considered, the first in which the rooms are at equal temperature, and the second in which there is a temperature difference between the rooms.
The flows were examined using a small-scale model of a revolving door and with fresh- and
salt-water solutions to represent temperature differences. The results presented herein reveal
how the transfer of air across a revolving doorway depends on the rotation rate and temperature