An experimental investigation has been carried out to study the acoustic interferences in vortex-shedding from a circular cylinder in a crossflow subjected to the acoustical vibrations whose direction is normal to the axis of the cylinder, and in particular, to search for the correlation of vortex-shedding along its axis. The results indicate that the effects of the acoustical vibrations whose direction is normal to the axis of the cylinder are similar to that of the acoustical vibrations directed along its axis on the vortex-shedding from the cylinder, and both vibrations increase the spanwise correlation of the cylinder wake. The acoustic frequency which produces powerful effects on vortex-shedding corresponds to the frequency of laminar-turbulent transition wave in a separated shear layer, and there are critical sound pressure levels in these acoustical vibrations.

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Apparatus placed in a clean room have great influence on the flowfield. Furthermore such flow obstacles often generate airborne particles into the airflow. Thus, it is very important to clarify the flowfield and contaminant diffusion field around flow obstacles. In this paper, the airflow distribution and the contaminant diffusion field in a conventional-flow-type clean room with flow obstacles in various arrangements are analyzed by means of model experiments and 3-D numerical simulations. The correspondences between the simulations and the experiments are fairly good both for the velocity field and for the contaminant diffusion field. On the basis of this validated procedure, further analyses of the airflow in a clean room with flow obstacles variously arranged are conducted by means of numerical simulations based on the k-ε turbulence model. From these analyses much useful information concerning the velocity field and the contaminant diffusion field around obstacles and concerning the influence of flow obstacles on the entire flow field is obtained.

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An investigation with questionnaire was conducted in summer and winter in order to find out the problems of present home water heaters and their proper design route. The subjects of the investigation are the inhabitants of apartments constructed by the Housing-Urban Development Corporation (HUDC), that construcued by private companies equipped with an overall central heating system for hot water supply, and detached houses, which covered 21 areas in total. The respondents were selected in consideration of a balanced mix of the kinds of home water heaters with the cooperation of HUDC and Tokyo Gas Co. Ltd. The valid replies amounted to 477 in the summer survey and 319 in the winter, and were classified into 8 groups according to the hot water supply systems. The results are summarized as follows. 1) In the case of filling bathtabs, the lack of hot water flow rate mostly spoils the comfortableness. 2) Hot water temperature of 60℃ is nearly satisfactory, except for special purposes such as removing oil stains. 3) The capacity of instantaneous water heater should be held down to class-4 (output of 6000kcal/h) for the sake of convenience. 4) The present level of temperature control systems is not considered fully satisfactory, especially for taking showers. 5) Water temperature or flow rate fluctuates most frequently in case that hot water is used in two or more places in the same apartment, irrespective of kind of water heating equipments. 6) In selecting an instantaneous water heater for installed central system, attention should be paid not only to its heating capacity but also to the controllability of water temperature. Automatic water temperature control as well as the heating capacity reduction devices are desireble for the comfortableness of users. 7) Most users wash their tableware and their face with the running water. 8) Showers were taken at a relatively high frequency although it is only recently that showers began to be equipped in Japanese homes. 9) Among the users of heating systems which share the same heat source for hot water supply and for room air-conditioning, the cost of fuel for the hot water supply is considered that it is a financial burden, however, can be made up for due to the improved convenience. 10) The most users replied that they were satisfied with the present water heating equipment as an overall judgement, especially for its convenience.

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The facilities of a hospital are required to have a variety of special functions. These include around-the-clock service that fully integrates treatment, research, training and living accommodation facilities. Moreover hospitals must also have a carefully controlled and comfortable environment. It is necessary to balance all these requirements and to ensure the most suitable controlled administration. Although one of the present authors has collected field data over many years related to this subject and has released research reports on the amount of energy consumed, there are few statistical analyser case studies on the reliability analysis of hospital facilities. Also, since the facilities mentioned above have not been studied as an integrated system, the interrelationship between the facilities, as parts of a whole system, is still unclear. The present study seeks to clarify qualitative tendencies and characteristics about the reliability and maintainability of hospital facilities. The Weibull analysis has been employed for quantitative consideration.

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This paper is the second report of our series of studies on the method to determine a velocity distribution from video images of visualized flow through image processing and numerical calculations. In the first report, we described the progress and background. the advantages and disadvantages of this technique, and the purpose of our studies. In this paper, we represent the outline of the system constructed in our laboratory, some examples of measurements, and the result of an experimental estimation of errors which arise in measurement. The system consists of a camera, a VTR, an image processor and a microcomputer. Flow images visualized with suspended tracer particles are once recorded on the VTR. The procedure to obtain velocity distribution is as follow; 1) An arbitrary selected one frame image is transmitted to the image processor. 2) The image is corrected to an image with uniform background, and subsequently it is reduced to a binary image. 3) The centroid coordinates and projected areas of tracer particles are calculated. 4) Other consecutive three frame images are treated simultaneously, and a set of data obtained from four frame images is transmitted to our university's computer, ACOS1000 or ACOS2000. 5) Velocity vectors are extracted by the tracer tracking method which was explained in our first report 6) Inadequate vectors are eliminated, where change of tracer area, tracer acceleration and velocity deviation are adopted as criteria for the judgment. A microcomputer version, in which inadequate vectors are eliminated manually, is also prepared. As examples of application a stationary vortex or a Karman vortex street behind a rectangular column in the water and an air flow in a ventilated room model were measured. As a tracer, styrofoam powders (for water) or metaldehyde aggregates (for air) were used. In every case, more than one hundred vectors are extracted from a set of data and resultant velocity distributions were considered to be reasonable. The error which arise in measurement was estimated through the velocity measurement of circular marks pasted on a turntable. The true velocity of a mark was calculated from rotating speed of the turntable and turning radius. The difference in declination between measured and calculated vector and the relative error of vector magnitude decreased as the mark displacement expanded. Hence, a measurement within 0.03 rad of declination error and within 5% of relative error of vector magnitude could be achieved provided that image sampling intervals are selected adequately.

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Conventional commercial building air-conditioning systems typically employ heat storage systems that have sufficient heat source capacity to achieve the utilization of recovered waste heat and night electric power, and to meet peak instantaneous loads. In light of the increasing popularity of these systems, a need exists for the prediction of the daily loads of air-conditioning system took place in a systematic fashion. This work is concerned with a prediction problem for the daily loads by taking account the Autoregressive Integrated Moving Average (ARIMA) model. Some of technical considerations are examined. At the end of each day (at 22:00), the modelling is first done for a set of observed data by taking into account the ARIMA model. In this modelling procedure, the historical load profile data are directly used but the ambient temperature profile data are not used. Next, this ARIMA model obtained above is used to predict the daily load for the next day. The load profiles are updated every day on the basis of the newly obtained load data. The differences between predicted and actual loads are examined for days 266 in 1987. There is generally good agreement between predicted and actual loads. The strategy algorithms are now executed to update the nominal operation of the heat storage system to meet the predicted load for the next day.

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This study has been made on the mechanisms of head loss in turbulent flow, and shows quantitatively that head losses are caused by the flow impact of fluid on the wall. The author has introduced theoretical equations which express the loss coefficients for miter bends; these equations well represent the actual phenomenon. In addition, the theoretical equations are modified by coefficients which were determined on the basis of the experimental results of many researchers.

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In casting and welding workshops, a large amount of fumes is generated from various heat sources. As a countermeasure against such fumes, general ventilation systems are usually used jointly with local ventilation. A lot of reports has been given on the general ventilation in workshops over a long time. However, various problems have been left unsolved in the actual factories adopting general ventilation. For example, a venting condition is dependent on weather or season, namely, a good venting condition occurs when it is fine weather, but a phenomenon that fumes stay stratiformly at a certain height is observed frequently in rainy weather. In this report, venting flows in a simple model with a heat source on the floor are simmulated numerically in order to investigate the appearance of the natural venting in workshops generating fumes. The P-V method is used as a calculation procedure and also the k-ε model is used for turbulent model. As the results of numerical calculation are well coincide with experiments, it becomes clear that the natural venting characteristics can be well estimated by numerical calculations using the k-ε turbulent model. Some series of numerical calculations were performed to investigate the influence of roof temperature and opening sizes on the venting characteristics. The followings have become evident from the calculation results. 1) The larger the opening size becomes and the higher the roof temperature is, the more air change rate increases. 2) The thermal stratification is formed when the roof is under an adiabatic condition. In this case, it is observed that the plume rising from heat source falls along the roof and the walls and then is entrained again in the plume at the height of thermal stratification. 3) When the roof is cooled, the thermal stratification is not formed any longer. In this case, the downflow containing a lot of fumes reaches almost to the floor, and the results that the working spaces are contaminated by fumes are supposed.

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The purpose of this study is to introduce the equations to estimate the water demand in various buildings. This paper describes on elementary school and junior high school as the sixth installment of this series. We executed the investigations of water uses in elementary school and junior high school being in the major 11 cities of Japan in the same way as the previous papers. In last paper, the first repost about school, we clarified the properties of building and equipment, and the conditions of water demand. Then we exhibited the approximate quantity about the estimate of building scale and equipment numbers, and we examined about the index of appliance numbers including users estimate. Then we analysed these factors using by the Quantity Theory Cluster III and clarified the relation between these item-categories. In this paper, the second report about school, we analysed about water demand. We clarified the pattern of water use and primary water consumption. After that, we introdused multidimensional equations to estimate the water demand per unit school building area and per unit person in school using the multiple regresssion analysis.

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