Nobuyoshi Kiyota

Wind Pressure and Air Flow in a Full-Scale Building Model under Cross Ventilation

Abstract The observation of wind pressure acting on the wall and floor of a full-scale building model under cross ventilation was carried out. The measurement of air flow was also undertaken, and the existing prediction theory of the air flow rate, namely the orifice flow equation, including the discharge coefficient, was evaluated for its accuracy. At the same time, a method of predicting the discharge coefficient has been proposed and tested. In conclusion, a tentative relationship between the discharge coefficient and the difference of wind pressure coefficient across the opening has been developed. In addition, the background concerning the difficulty of using the orifice flow equation has been described.

Study of the Airflow Structure in Cross-Ventilated Rooms based on a Full-Scale Model Experiment

Abstract Cross ventilation to reduce cooling energy is one of the most important techniques for maintaining a comfortable indoor environment in hot and mild seasons. However, at present, it is difficult to design the indoor environment under cross ventilation because there is insufficient knowledge to evaluate the effect of cross ventilation quantitatively. To develop an understanding of the flow characteristics a full-scale model experiment was performed in a large wind tunnel to examine airflow properties in a cross-ventilated space. The purpose of this paper is to clarify the airflow structure in the cross-ventilated room in relation to wind direction. The key factors determining the airflow structure in the space were found to be: the main current region, rebounding and changing flow direction, deflected flow, surface flow and circulating flow. It was observed that the main air current tends to travel in a straight line until it collides with obstacles. On collision, the flow changes direction and deflected flows are formed over and/or under the main current. When there is enough space alongside the main current region, a circulating flow is formed in each room. The room mean velocity was found to be dependent on the path of the air current. When the main current is well defined, a relatively low value of mean velocity is observed. When the main current is divided, the room containing the inflow opening has a relatively high velocity.

STUDY ON MAGNETIC SHIELDING EFFECT AROUND THE ELECTRIC POWER LINE IN VARIOUS MATERIALS OPENING CONDITIONS

In magnetic shielding with the opening of the magnetic material around the electric power line, I confirmed the difference of effect in various opening conditions by an experiment. The results are as follows. The shielding effect was low under conditions of opening rate more than 30%. The difference by opening pattern was small, but the effect with the staggered pattern was high in a specific condition. By the method to increase area of each opening, the effect decreased in the neighborhood of the power line, but there was not the difference in the distant place.

THE INFLUENCE OF THE AIR FLOW OF SEA BREEZE ON URBAN CLIMATE

In this paper, we carried out the field measurement in the urban district in Hiroshima City formed on the delta in Ohota River. We measured wind velocity and temperature in the sea breeze in the summer. We made an analysis of the relationship between the air temperature and the instantaneous wind velocity. Results are as follows. In case of Eastern and Western Street near the river, there is the relationship between air temperature and the wind direction: the air temperature falls when it blows from the river. In case of the road at Northern and Southern Street on the inland, there is a correlation between air temperature and the instantaneous horizontal velocity. In case of the Eastern and Western Streets where there are many the high-rise buildings, there is a correlation between air temperature and the vertical velocity. The case on the bridge at Eastern and Western Street, there is a correlation between air temperature and the horizontal velocity.