The flow characteristics of the two-phase flows in a 100 µm circular horizontal microchannel have been investigated experimentally and analytically. In the experiments, nitrogen gas and one of four liquids (distilled water and 4.8, 49, 100 wt% ethanol in water) were injected through a T-junction type mixer to the microchannel, having smaller diameter than that of the mixer. Both quasi-homogeneous flow and quasi-separated flow was observed depending on gas and liquid flow conditions. Furthermore, the data on void faction, frictional pressure drop and interfacial friction force were found to be larger in the quasi-homogeneous flow than the quasi-separated one. In the analysis, empirical correlations of the liquid-wall friction force and the gas-liquid interfacial friction force were developed respectively for the quasi-homogeneous and the quasi-separated flows. By substituting these correlations into an analytical code based on a one-dimensional two-fluid model, we calculated the void fraction. The calculations reasonably agreed with the data irrespective of the quasi-homogeneous and the quasi-separated ones.

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In order to survey the wind characteristics of Japan, where mountainous terrain is predominant, a large amount of wind data (NEDO Field Test Data) from more than 300 measurement sites in Japan were analyzed in detail, particularly the turbulence characteristics. As a result, it was found that the profiles of the 90% quantiles of turbulence intensity estimated in all of the NEDO Field Test Data are well approximated by the IEC Normal Turbulence Model (NTM). However, the turbulence intensity levels of more than 65% of the measurement datasets exceed the most severe turbulence category (Category A) in IEC 61400-1 (Ed.3). We therefore conclude that the present IEC turbulence model for wind turbine design does not reflect the severe wind conditions of mountainous countries such as Japan. This is considered to be one of the main reasons for the frequent problems of wind turbines in Japan. New criteria for the NTM are proposed to overcome this problem. The appropriateness of the new criteria to the severe wind characteristics in Japan is also discussed.

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Wind characteristics were measured at one of the sites suitable for wind turbine generation in Japan using an ultrasonic anemometer and cup anemometers. In particular, the ultrasonic anemometer is considered to be more suitable for analysis of turbulence and gust characteristics due to its lack of moving mechanisms. The reliability of the NEDO Field Test Data for turbulence intensity analysis used in the first report of this study was evaluated by this measured data. Gust characteristics in the wind models of IEC 61400-1 (Ed.3) were also analyzed, and compared with the current IEC gust model and new gust criteria obtained by integrating the new turbulence criteria proposed in the first report. As a result, it was found that the most extreme gust event measured in this study would be more severe than the Extreme Operating Gust (EOG) model in the current IEC 61400-1 (Ed.3). It was also found that the amplitude of the EOG model is adjusted by incorporating the new turbulence criteria. The applicability of the new turbulence criteria to other wind models was therefore confirmed to some extent in this research.

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A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio. Therefore, it is a good candidate for use as a self-starting turbine. Furthermore, it has low noise and excellent stability; therefore, it has attracted attention from the viewpoint of applications as a small wind turbine for an urban district. However, its maximum power coefficient is extremely low (10 %) as compared to that of other small wind turbines. In order to improve the performance and the flow condition of the cross-flow rotor, symmetrical casings with a nozzle and a diffuser are proposed and experimental research with two types of symmetrical casings is conducted. The maximum power coefficient is obtained as C_pmax = 0.17 for casing 2 and C_pmax=0.098 for casing 1. In the present study, power characteristics of the cross-flow rotor and those of the symmetrical casings with the nozzle and the diffuser are investigated. Then, the performance and internal flow patterns of the cross-flow wind turbine with the symmetrical casings are clarified. After that, the effect of the symmetrical casings on the performance of the turbine is discussed on the basis of the analysis results.

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This paper describes the effect of the shape parameters on the flow resistance of a perforated plate used as a vent plate or cover for electronic equipment. In this study, we focused on the effect of hole shape and presence or absence of holes near the outer edge as the shape parameters of a perforated plate. The study is about electronic equipment designed to be air-cooled by natural convection. To demonstrate the effect of hole shape as a usable parameter for design engineers, the design of experiment (DoE) method was used to design the experimental samples of perforated plate. The effect of the outer edge was evaluated by comparing the flow resistance of perforated plates with and without holes on the outer edge. In addition, the flow resistance data obtained in this study was arranged as an empirical formula.

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This paper describes a water leak test of roof tiles. The 100 roof tiles were set up on 10 lines and 10rows on the pitched roof in the downstream of the flow from the wind tunnel. The flow velocity was increased gradually from the low velocity to the high velocity, and the effects of the wind on the roof tiles were investigated by the water leak test. The situation of the water leak test was filmed by video camera. Two accelerometers were simultaneously used. The roof tiles which showed significant vibration at any velocity were found in a series of experiments and the accelerometers were attached to the two neighboring roof tiles on the model roof. The water leak phenomena in the experiment by using the artificial rainfall apparatus are discussed in this paper. Some mechanisms with relatively large amplitudes at low-frequency vibrations, which caused water leak phenomena were made clear.

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In this study, numerical analysis of cavitating three-blade cyclic flat-plate cascade is performed with paying attention to cavitation surge which is a type of cavitation instabilities. A numerical method employing “locally homogeneous model for compressible gas-liquid two-phase medium” is applied to solve the unsteady cavitating flowfield. From results of numerical analysis, few typical tendency of cavitation surge which is well known in experiments was reproduced numericaly, that frequency of cavitation surge decreases with lowering σ, and that cavitation surge is easy to occur at low flow rate condition. Additionaly, mechanism of pulsation phenomenon of cavitation surge in flat-plate cascade was clarified, that collapse pressure of cloud cavity in downstream of cascade propagates upstream on contact with re-entrant jet which is flowing backward inside a sheet cavity and causes oscillation in upstream pressure, also that negative angle of attack and choking of cascade throat are considered to cause of oscillation in flow rate. About dynamic transfer function of cavitation, certain degree of possibility is confirmed in quasi-steady mass flow gain factor M_quasi and cavitation compliance K_quasi for prediction of occurrence limit of cavitation instabilities. Additionally, for prediction of frequency of cavitation surge, it was confirmed that local cavitation compliance K_local is more available than quasi-steady one.

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In recent years, it is strongly required to improve the Chemical Mechanical Polishing (CMP) technology for Cu. The conventional Cu-CMP slurries, however, have serious problems relating to detrimental impact on environment, because it includes a lot of organic compounds and abrasives. In this study, a new Cu-CMP method, that is, the polishing method utilizing vacuum ultra-violet (VUV) light irradiation and an electrolyzed water was proposed and developed in order to overcome the above-mentioned problem. In the newly-proposed method, the Xe excimer lamp was adopted as the VUV light source. The lamp has a sharp peek of the wave length at 172 nm, and can generate an ozone gas from decomposition of oxygen. The effects of the VUV light irradiation for Cu-CMP are thought to be as follows; 1) an oxidation effect by generated ozone, 2) a photoelectric effect for Cu substrate. Then the polishing experiments for Cu substrate were carried out with in-situ VUV light irradiation. The experimental results revealed that the developed method was effective for obtaining precise smooth surface, namely, the mirror-finished surface under 1 nm Ra was achieved. From the result, it was found that the developed polishing method has an electrochemical effect for polishing, namely, the amount of OH^- groups and the density of oxygen or pH of polishing fluid have a strong influence on Cu polishing process.

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