Studies on building layout for effective cross-ventilation

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Several cases of numerical simulation and wind tunnel tests of turbulent air flows in and around buildings were carried out for better utilization of cross-ventilation.k-e 2-equation model is adopted as a mathematical model of turbulence. The main results are summarized as follows : (1) The result of numerical simulation of an air flow around a high-rise building indicates good agreement with the distribution of wind velocity vectors in the whole simulation area measured by a tandem-type hot wire anemometer in a wind tunnel test. (2) The wind pressure coefficients on the walls facing to a narrow space between two houses are larger than those on a side wall of a single house. When the inter house gap is narrower, the change of the wind pressure in the wall is greater. (3) The absolute values of wind pressure coefficients on all the walls of regularly aligned low-rise houses are smaller and close to 0, when the building coverage ratio is larger in all the cases of wind direction. (4) The … More influence of a high-rise building model on the wind pressure on the walls of low-rise house models which are aligned regularly with a building coverage ratio of 25% around the building model becomes greater, when the building model is higher. (5) The wind pressure coefficients of low-rise house models located in the windward side of a high-rise building model are larger and those in the leeward side are smaller, when the building model is higher. (6) Numerical simulation methods employing partial refine technique are attempted successfully for the better analysis of cross-ventilation which is a continuous air flow phenomenon from the outside to the inside of a model building. (7) The estimate of a cross-ventilation rate needs total pressure drop coefficients at all the openings of a model building, because the air flow by cross-ventilation passing through the indoor space conserves its kinematic energy. The ventilation rates calculated by the conventional method based on static pressure differences and discharge coefficients of openings are smaller than actual cross-ventilation rates by 19-38%. (8) The total pressure drop coefficients at the inlet opening and that at the outlet opening of a model building are smaller than 1.0, and the latter is about a half of the former. The total pressure drop coefficients at the openings of partitions change greatly by the position of the partitions of the same shape. Especially, it is large when the partition is located to be a barrier of cross-ventilation. Less