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An advanced micro-bubble generator with a spherical body in a flowing water tube was invented by Sadatomi in 2003. In the present paper, as an industrial application of the micro-bubble generator, a bubble-jet-type air-lift-pump also invented by Sadatomi in 2005 has been presented together with the results of its feasibility test. In the test, effects of particles size, submergence ratio (=the riser length submerged in water divided by the total riser length), and water and air supply rates to the bubble-jet generator on the pump rerformance have been studied. Yoshinaga-Sato model for predicting water and particles discharge rates has been modified and tested against the present experimental data to confirm its validity. The results of such experiments and analyses are reported in this paper.

A new theory is proposed in this paper explaining the generating of upwellings in ocean currents near the shore and in rivers. Up until now, there have been the bursting phenomenon theory and the cork-boil Eddies theory about upwellings. The proposed theory in this paper is based on the Ekman Pumping theory and is completely different from previous theories. The validity of this newly proposed theory has been proven through numerical calculations.

Cold crucible is a levitation melting device, and it is a useful device for melting metal without contamination because the molten metal is levitated by electromagnetic force in the crucible. In this paper, three-dimensional eddy current distributions in cold crucibles are analyzed by using an integro-differential method. In order to reduce computer resources for the analysis of eddy current distribution of the cold crucibles, the authors employed a current sheet approximation for eddy current distribution because penetration depth of the eddy current is relatively small in comparison with the dimension of the conducting bodies. The eddy current distributions approximated by current sheets are solved by an integro-differential method using an electric vector potential. Furthermore, magnetic flux density, power loss, Lorentz force and levitation force of the molten metals are obtained from the solved eddy current distribution. In this paper, eddy current distributions and power loss distributions are investigated.

Characteristics of the most unstable wave of baroclinic instability are often interpreted as resonance of two Rossby waves in the upper and lower layer. In this paper, we considered this interpretation in more detail to deepen our understanding of baroclinic instability.

In this paper, aerodynamic characteristics of the cross flow type of wind turbine were studied experimentally by using sub-scale model, considering the effect of guide vanes and its arrangement. The aerodynamics characteristics of the turbine for wind flow direction were discussed by reference to the power and the torque coefficients correlation of tip speed ratio for various combinations of approaching optimized guide vanes number and optimal configuration.

On designing and developing products, the finite element analysis of three dimensional eddy current-thermal problems is very useful. This paper shows effectiveness of a large scale eddy current-thermal analysis for a transformer tank using the domain decomposition method.

The spray combustion is applied to various practical combustors such as a diesel engine, a gas turbine, etc. However, the spray combustion is the very complicated, unsteady and inhomogeneous physicochemical phenomenon composed of preheating, evaporation, mixing, ignition, combustion and quenching, etc. Chiu et al. considered the spray combustion field with the concept of group combustion, and proposed that the group combustion can be classified into four modes in terms of group combustion number. In this paper, we examined to improve Chiu’s group combustion mode using the numerical analysis on gas phase combustion process in three-dimensional inhomogeneous concentration and temperature fields of methane-air mixture. We arranged many fuel points using random variables instead of fuel droplets, and changed the initial equivalence ratio and fuel point diameter. We obtained the following results; 1) The group combustion is classified into five modes in terms of the initial equivalence ratio and fuel point diameter. 2) The ignition occurs in each fuel point when the mixture gas is lean, while the ignition occurs in the area with fuel point closely spaced when the mixture gas is rich. 3) "The initial equivalence ratio / fuel point diameter" is the appropriate parameter of the group combustion of gas phase.

Natural convection is suppressed in space environment due to the weightlessness. Only centrifugal force is utilized currently to drive gas-phase thermal convection in space. This paper presents an alternative way to drive thermal convection. From the investigation of combustion oscillation in rocket motors, a new thermal convection had been found in stationary acoustic fields. Analyzing the phenomena, acoustic radiation force is found to be the candidate driving force. With a simplified system using a hot wire as a cylindrical heat source, the characteristics of the convection in acoustic field are investigated experimentally. A numerical modeling that includes the radiation force succeeded in reproducing the convection. Knowledge for further application is obtained., 資料番号: AA0063349021

The popularization of both small-sized and large-sized wind turbines is indispensable for the popularization of wind power generation. Though many small-sized wind turbines are manufactured in the world, most of them are not suitable for the special wind conditions in Japan, which are characterized by frequent change of wind direction and heavy turbulence. This paper describes the results of the characteristics test of a small-sized perpendicular-axis type wind turbine to identify the conditions of a small-sized wind turbine suited to Japanese wind conditions.

Structure of single bubble is classified into six types. Although bubbles are often seen in everyday life, a couple of types, a water droplet drifting on water surface and an anti-bubble, that is water droplet wrapped with air film, are regarded as unfamiliar phenomena. Mechanism of the air film stability is discussed in comparison with soap film stability. This paper presents a possible mechanism that sliding and rotation of a water droplet stabilize floating droplet and anti-bubble with preventing air films from losing their thickness. Transpoting air by capillary wave on the droplet surface is also a candidate of the stabilization mechanism. Step-by-step decrease of diameter in collapse of a droplet is explained by the concept of capillary wave.

In this paper we attempted to develop a low-noise 'Active Turbulence Generator (ATG)' for aerodynamic noise measurement in a large scale turbulent flow field. The aerodynamic noise from the developed ATG was only 10 dB larger than that of the conventional wind tunnel. Aerodynamic noise from a rearview mirror was measured to estimate sound generation effect on turbulence intensity. The experimental result showed that the edge tone of the rearview mirror was disappeared in the case of strong turbulent flow field. Aerodynamic noises strongly depend on the turbulence intensity and eddy scale of incoming flow. The turbulence of incoming flow is important parameter to estimate flow around real cars. The active turbulence generator is one of the useful devices to simulate real road simulations in wind tunnels., 資料番号: AA0049208017, レポート番号: JAXA-SP-05-012

This paper presents current status and issues of aircraft drag prediction using numerical methods based on Reynolds-averaged Navier-Stokes equations (RANS) in JAXA. Several results on an airfoil and aircrafts show the prediction of aerodynamic drag is very sensitive to grid density and numerical schemes as well as transition in boundary-layer. Although state-of-the-art RANS CFD can not satisfy the requirement for aerodynamic design of aircrafts enough, it already provides almost the same reliability as wind tunnel tests in some cases. To overcome the issues in the prediction reliability, tighter cooperation between numerical and experimental methods is important besides efforts to improve numerical schemes and turbulence models., 資料番号: AA0047776019, レポート番号: JAXA-SP-04-002

The large sized solar arrays of satellite are installed in the fairing section of by being folded up. So the thickness of air layer between two panels is very thin comparing with the in-plate size of the panel. Because the panel is extremely light, the vibration of the panel is affected by the air layer. This paper presents that the effects of layer thickness on frequency of a panel including viscous, incompressibility air., 資料番号: AA0047427036, レポート番号: JAXA-SP-03-002

The present paper has dealt with the one-sidewall cooling effect of spherical adsorbent paticles packed in a rectangular bed on water vapor adsorption characteristics by a 2-dimensional numerical analysis. The analysis model was considered that one-sidewall of a rectangular packed bed with the homogeneous spherical silica-gel particles was cooled and another walls were adiabatic. The moist air flowed into the rectangular packed bed with spherical adsorbent particles. The silica-gel B with high adsorption ability over high relative humidity was selected as a suitable adsorbent. Numerical results revealed the effects of moist air inlet humidity and airflow velocity, size of spherical silica-gel particles and width of the rectangular packed bed and the sidewall cooling terperature on the amount of water vapor adsorption., 住宅・ビル空調分野では、省エネルギーの促進や室内空気質そしてアメニテイ性の向上が米国やカナダように一部義務付けている状況あり、今後室内空気の調湿や換気に伴う空調負荷の増大が予想される。このような背景のもとに、大量に賦存する低温排熱の利用、省エネルギー促進そして室内空気環境の快適性志向をカバーする環境親和型熱技術（グリーンサーモテクノロジー）の最右翼である熱サイクル機器として、吸着剤を用いた吸着熱式冷凍機やヒートポンプそして調湿機やデシカントクーリング機器等がある。吸着剤を用いたヒートサイクルは、古くて新しい技術で、環境に優しい技術と言うことで米国や欧州等で開発普及が進んでおり、我が国の代替冷媒を用いた蒸気圧縮機型冷凍機の展開と対比するものである。これら吸着剤を用いた空調関連の調湿や調温利用以外に、吸着剤の水蒸気の吸着及び脱着過程において、水分の蒸発・凝縮潜熱に相当する多量の熱授受があることから、吸着剤は蓄熱材として利用の可能性がある。特に高温多湿な我が国の気候環境においては、湿り空気中の水蒸気を吸着剤に吸着（除湿）する際に発生する吸着熱（放熱）を暖房熱源等へ利用し、その脱着再生（加湿）においては排熱や太陽熱等を利用する、いわゆる化学蓄熱の構築が可能となる。従って、本基礎研究は、一般に普及している低温脱着が可能なシリカゲル吸着剤を蓄熱剤として利用することを前提として、まず冷却による平衡状態に至る吸着特性向上を数値計算で検討するものである。対象とする吸着系は、球状吸着剤を充填した矩形充填層に湿り空気を流動させるもので、吸着性能向上特性は矩形充填層側壁からの冷却による効果を種々の因子（冷却温度、湿り空気流入湿度、平均空気速度、球状吸着剤粒子直径や充填層の寸法）のもとで明らかにするものである。

A strong sound field produced in an air-filled tube generates steady pressure distribution, acoustic streaming and thermoacoustic effect as nonlinear phenomena of the finite-amplitude oscillation of air column in the tube. One of the applications of these phenomena is the promotion of heat convection in an air-filled duct, When a sound field is superimposed on a Taylor-Benard convection generated in a horizontal duct, coupling of acoustic streaming and thermoacoustic effect with the convection is experimentally observed as the change in structure of the convection field, and it promotes heat transfer. This paper describes a quantitative analysis of the coupling phenomena using a numerical method. The calculated results show the variations of velocity, acoustic Reynolds stress and temperature distributions in the Stokes layer with different values of temperature difference between the upper and lower walls of the duct. With these results, the effects of coupling of acoustic streaming and thermoacoustic effect with convection are discussed.

Some hydrodynamic aspects of tidal inlet defined as the relatively short channel connecting bay and ocean is treated. Often such system exhibits irregular geometry and complicated flow patterns at the ocean- and bay-side. As a result of the large variations in depth and width, the velocity field contains both vertical and horizontal eddies. These eddies often are dominant features rather than perturbations on the main flow.In the context of this paper, an idealized and simple model basin is treated. It is because that this research is aimed to improve the fundamental understanding for the inlet-related problems.Only tidal forcing is considered. Emphasis is on the bay response of water level to outer sea, tidal exchange process through the inlet and local sea-bed variations near the inlet.

The flow in enclosed non-isothermal space such as air-conditioned room is considered desirably as non-isotropic turbulent flow due to gravitational effects. In this case, the Reynolds stresses and the heat flux terms in the transport equations induced by time-mean should be treated as non-isotropical values including buoyant effects of a gravitational field. The approximate method based on the expression by Launder et al is used in the analyses of this paper. Namely, the Reynolds stresses and the heat flux terms are expressed algebraically by the use of buoyant effects in addition to eddy kinematic viscosity and eddy diffusivity of isotropic turbulent flow. In order to investigate the justice of this method, the calculation about free shear flow, jets and turbulent flow in pipe are carried out. The calculated flow velocity and air temperature by three dimensional analyses of finite element method are compared with the measured values in air conditioning chamber of container type., 長崎大学工学部研究報告, 13(21), pp.187-194; 1983

This paper is concerned with an experimental observation of horizontal cylindrical ice before the nozzle from which moist air is jetted in forced convection. It is found that there are some results obtained in the range of Reynolds number Re from 3,000 to 120,000. The relationships between Nusselts number Nu and Reynolds number Re are discrived by the next experimental equations, local maximum Nuo=2.9Re0.46 mean Num=0.73Re0.58, 長崎大学教育学部自然科学研究報告. vol.31, p.133-142; 1980

This paper was written to experiment of fusion of cylindrical ice that was set in the vertical tube on the upward air flow. The experimental results, relationship dimensionless radius r* and dimensionless elapsed time until r* > 0.3 was linear.

In a curved channel there are spiral motions occurred by centrifugal force. And in an openchannel that consists of a main channel and flood plains, the flow has a complex turbulent structurebecause of interaction between flow in a main channel and it in flood plains. So it is difficult to clarifycharacteristics of an open channel flow in bend with flood plains.In this paper it is the objective to elucidate the turbulent structure of this flow by measurementsof velocity and flow visualization. From experimental results it is comfirmed that three independentspiral motions exist in bend with two flood plains.

This paper was written to experiment of fusion of cylindrical ice that was set in the vertical tube on the upward air flow. The experimental results, relationship dimensionless radius r* and dimensionless elapsed time until r* > 0.3 was linear., 長崎大学教育学部自然科学研究報告. vol.26, p.115-122; 1975

The flow in enclosed non-isothermal space such as air-conditioned room is considered desirably as non-isotropic turbulent flow due to gravitational effects. In this case, the Reynolds stresses and the heat flux terms in the transport equations induced by time-mean should be treated as non-isotropical values including buoyant effects of a gravitational field. The approximate method based on the expression by Launder et al is used in the analyses of this paper. Namely, the Reynolds stresses and the heat flux terms are expressed algebraically by the use of buoyant effects in addition to eddy kinematic viscosity and eddy diffusivity of isotropic turbulent flow. In order to investigate the justice of this method, the calculation about free shear flow, jets and turbulent flow in pipe are carried out. The calculated flow velocity and air temperature by three dimensional analyses of finite element method are compared with the measured values in air conditioning chamber of container type.

Measuring for a flow direction and the velocity is necessary for analysing on a pollutant diffusion in model water-way and on a convective heat transfer. A new method, by which a direction of cubic flow is measured, has been developed extending the principle for a two-dimensional flow. In the paper, the principle of measurement and result on the calibration are described.

This paper is concerned with an experimental observation of horizontal cylindrical ice before the nozzle from which moist air is jetted in forced convection. It is found that there are some results obtained in the range of Reynolds number Re from 3,000 to 120,000. The relationships between Nusselts number Nu and Reynolds number Re are discrived by the next experimental equations, local maximum Nuo=2.9Re0.46 mean Num=0.73Re0.58

Clearly discernible fronts are often observed at the margin of river water discharged into the sea. The existence of coastal currents is thought to be essential to the formation of such fronts. However, their detailed formation mechanism has not been studied extensively so far. In the first part of this paper, we demonstrate the importance of the existence of the coastal current on the formation of fronts by reproducing the river water front in an experimental tank simulating coastal geographic condition. In the second part, steady-state surface gravity currents are produced in a laboratory flume as an idealized two-dimensional model for river water front. Experimentally obtained data include interfacial profile of the surface gravity currents and velocity and density profiles in the vertical. The entrainment coefficients calculated from these data exhibit the same dependence on the Richardson number as the data obtained with other two-layered flow phenomena. Interfacial profiles are compared with the calculated profiles obtained from two-layered flow equations which take both interfacial shear and entrainment across the interface into consideration. A good agreement is obtained between calculated and measured interfacial profiles by a suitable choice of the parameters in the flow equations and the result gives the non-dimensionalized length of the river water front as a function of the densimetric Froude number.

All turbulent jets eventually become buoyancy-dominated plumes far away from the origin, even if they have very large initial momentum flux. In this paper we derived new relationships between velocity and temperature for vertical turbulent plumes in quiescent fluid. These in effect give the local Richardson number of plane and round plumes. The relationships are in good agreement with the experimental data., 資料番号: NALTR0763000, レポート番号: NAL TR-763