A fuel rod of VHTR (Very High Temperature gas-cooled Reactor) which is planed by JAREI has rectangular projection parts, called "Spacer ribs", to make the coolant flow in a concentric annular channel.
To investigate the effect of a spacer rib on heat transfer characteristic, the surface temperature distribution was measured using thermosensitive liquid-crystal-film adhered on the heating plane, under the laminar, transitional and turbulent flow conditions.

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Oil film method was applied to two types of hydraulic machines;
(a) a pump-turbine, and (b) a high head submersible multistage-pump.
In case (a), the flow near the cone and crown surfaces were studied, using the measurements of static pressure together. The purpose was to determine the appropriate location of a balance hole exit, which greatly affects the thrust characteristics. In case (b), the flow at the return guide vane was studied to improve the efficiency of the pump. The oil film method was very useful to get the information for improving the characteristics of hydraulic machines, in above cases.

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The latest diagonal flow reversible pump turbine has a tendency towards increasing speed. On that occasion, cavitation phenomenon in pumping operetions is a serious problem for the maintenance.
It is, however, very difficult to measure the impact pressure due to cavitation along the surface of the blades.The paucity of reports on the measurement of the impact pressure on the blades due to cavitation so far have prompted us to investigate it.
Thereupon, an experiment was made on the influence of the changes of rotating speed and runner vane opening on the change of pressure distribution, using a model of movable diagonal flow reversible pump turbine.The pressure distribution due to cavitation was visualized by Fujifilm Prescale(pressure detecting sheet).

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For the investigation of unstable or unsteady flow Phenomena such as a highly separated flow around a body, one should grasp the direction and situation of the body-surface flow at every moment.Though various surface tracing methods have been used in the visualization of limiting streamlines, most of them can only yield streak lines representing the mean direction of body-surface flow during a time.A few chemical film staining methods are able to follow flow fluctuation by changing the reacted color reversibly, even so the rate of response seems to be rather slow.In this respect, a new surface tracing technique is proposed by use of liquid crystal sheets which are known to be capable of showing quick response to temperature variation by reversible metachromatism, The visualization of surface flow near the tip on a three-dimensional hydrofoil model of marine propeller blade shape was carried out, in the circulating water channel, to examine the applicability of this method.Point heat sources made by electricall heated copper rods are inserted in the model surface and used as the tracer generators.For reference, surface tuft method was also executed.Photographs were taken at several attack angles to produce fluctuating flow for simulating that of an actual propeller blade rotating in the ship wake.The observed result shows that such a liquid crystal sheet method with point heat sources is quite available for visualizing the fluctuation of body-surface flow.

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A turbulent swirling air-flow in a straight pipe is visualized by use of tuft-grid Method. A contrivance is proposed in order to prevent a strong vibration of tufts.
Velocity distributions are also measured by hot wire anemometer and the velocity Ratio V_θ/V_z by hot wire measurement is compared with the flow direction by tuft-grid method.

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In general, it seems to be very important method to visualize eddies formed around a fish in order to investigate the fish propulsion, but only a few methods have been reported by this time.
In this paper, three methods of visualization are shown. One of them is a tracer method and the others are methods making use of the refraction of a light which passes through stratifies fluid. After pouring water into the box made of clear plastic plate with 5mm thickness, about 30% sugared water mixed with Chinese ink is slowly injected into water along a slender bar.
The light must be situated in the opposite side of the camera.
Fishes used in this experiment are a carp, a goldfish, a dace and a mudfish.

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A Gas mixture of Ar and Freon 12 was used to produce a transonic flow of Reynolds number of the order of 10⁶ in a shock tube. The positions of the shock wave on a NACA 0012 were observed with the shadowgraph method adopting plastic optical fibers as light guides and compared with Cook's experiment performed by using air as the driven gas. The results show that the optical fibers can be used satisfactorily for the shadowgraph and the gas mixture of Ar and freon 12 is useful for obtaining the transonic flow in a shock tube whose proof pressure is relatively low.

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In the steam tunnel, the condensation phenomena in a steam turbine cascade and a laval nozzle were visually confirmed by the color schlieren method. In a one-dimensional laval nozzle, when the wetness increases under the constant Mach number and Reynolds number, the condensation shock wave appears in the main stream and is transported towards upstream at higher wetness.
The similar phenomena were observed in a two-dimensional turbine cascade, and the condensation shock wave appears upstream of the wake shock waves normally observed in the superheated steam condition.

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In order to observe the asymmetrical compressible airflow, we have examined the density fields by the following methods.
(1) multidirectional interferometry,
(2) cross sectional density field reconstruction from it's projections.
The experimental values obtained by utilizing these methods on a flow field around a sharp cone at angles of attack were found to be in good agreement with the calculated density values.

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A new visualization technique is introduced to know the shape of liquid surface. This method, which we named 'K-Moire method' is excellent in the point that it is possible to see very small disturbances of the surface with high resolution compared with ordinary grid lighting Moire method.
In this paper detailed technique for the visualization is explained. The grid used here is made of nylon string 0.23mm in diameter which is arranged with 0.5mm pitch using screw notch.
The lines in the pattern observed is not defined as contour lines, but the pattern could be reproduced by digital plotter after numerical analysis.
Experimental examples are presented for simple surface shapes, which are paraboloid of revolution and combined vortex. For both cases the computer plots are shown together, and they agreed with experimental results pretty well.

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In order to clarify the dynamical switching mechanism of attachment jet by control jet, the switching process was observed by the visualization technique of flow pattern and pressure distribution applying Moire topography to free-surface water table.
The observations were performed at Froude numbers of 0.5 to 0.8, which correspond to Mach numbers of air jet, and at various control depths between 30 and 80 per cent of the attachment jet's supply depths.
It was found that the factors affecting the switching action are the initial deflection of the jet and vanishing, occasionaly reversing pressure gradient across the jet owing respectively to the momentum and the flow of the control jet. A strong vortex caused by control jet's entrainment keeps the jet from switching in its earlier stage.

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Flow visualization using photoelasticity has been applied to the two-dimensional flow over a wavy bed. Under the different conditions of the concentration and the temperature, aqueous solution of Milling Yellow dye has been tested in order to obtain the effect of birefringence. The results of shear stress measurement of the flow are compared with the theoretical neumerical solution. ITV has been used for the quantitative evaluation of the photo picture analysis.

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One of the authors Arai has occationally reported on the usefulness of the application of the gel birefringence method to the stress analysis of the flowing liquid. But isochromatic and isoclinic lines clearly showed remarkable change not only with the included angle of the wall but also with the direction of load. Any theoretical background for these observations has never been clarified. In the present paper, a theoretical derivation of the lines were performed by applying Moffatt's (1964) streaming function to the standpoint adopted by Philippoff (1976) on the birefringence analysis on Newtonian liquid. Herein calculated values were compared with practically observed ones obtained by gel birefringence method using 15 wt.% gelatin jelly.

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To make clear the flow behavior of a turbulent jet, the authors have applied the Schlieren method to the two-dimensional jet impinging obliquely on a solid wall. For flow visualization, the central parts of the two-heating the flowing air itself to eliminate the end effects of plane jet, e.g. the entrainment effect of ambient air or the boundary effect on side wall.
In the present paper, some photographic results of jet flow pattern are compared with each other, and the effects of the initial jet velocity (u₀), the distance(H) between nozzle and wall and the impinging jet angle (θ) on the behavior of impinging jet are discussed.

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When a lot of data are processed in a computer, flow visualization by such a figure process as drawing streamlines and equivorticity lines is very important to find new phenomena from the data. Here, some flow patterns are visualized on a X-Y plotter or a graphic display. In this method, streamlines or equivorticity lines are able to be plotted using stream function or vorticity at a constant interval for two-dimensional orthogonal curvilinear coordinates system. In this paper, an initial flow around a uniformly accelerated elliptic cylinder in an incompressible flue is analyzed from at rest by a finite-differnece method and time histories streamline and lines of constant vortcity are shown.

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A flow visualization with a smoke sheet method is applied to obtain the relationship between flow patterns and heat transfer for a combined natural and forced convection of developing laminar flow in rectangular duct. Characteristics of flow patterns and heat transfer results are explained in terms of Reynolds number and Rayleigh number.
The duct is placed long side horizontal as well as short side horizontal, and heated from two shorter side walls, and the opposite side of two walls are kept with heat insulator. The aspect ratios of the channel height to the width examined are 1/10 and 10, the range of Reynolds number and Rayleigh number are of 140.45 to 148.49 and 1.03X10⁷ to 3.16X10⁷, respectively.
The flow pattern is found, to be simillar to that of the case with one side-wall heating reported in reference (1) and (2) with some minor modification. The heat transfer results are related with the flow pattern observed. The flow rate of heat when the channel is heated from two side walls is shown to be much higher than the one side-wall heating.

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Prediction of maneouvring motion of ships is quite important in the view point of practical ship design and safety of traffics at seas. The understanding of flow field around ship hull and accurate estimation of hydrodynamic forces and moments on the hull makes the better prediction possible.
As an application of dye tracer method, flows around a simple shaped ship model with drifting angle were observed in a towing tank. Surface streamlines and trailing vortices were visualized by means of luminous dye tracer injected from holes on the model surface. Some knowledge on the structure of flow field and experimental techniques of flow observation were obtained. Results of observation were compared with those of qualitative measurements and calculation of potential flows.

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A stereophotography is often used in the field of photogrammetry, but is little used in measurement of a three-dimensional flow field because of the complexity of date processing.
In this study, the three-dimensional flow field around a circular cylinder is visualized by tracer method and the instantaneous positions of several tracers are measured by a stereophotography. The velocity by a stereophotography is also compared with the velocity by another method.

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Coloured slits method is a simple technique of three-dimensional visualization. This method has a limitation of range and somewhat rough estimation in the depth of a picture. However, it gives easily the loci of tracers in three-dimensional view, especially in a complicated flow pattern. In this paper, structure of turbulence in a pipe with squared crosssection was studied by means of this method. The pictures of flow patterns were taken with various convection speeds of camera in coincidence with local mean velocities of the flow at various position. Longitudinal vortices with nearly local mean velocities, two typical ejection patterns, that is, vortex type and abruptly ejected one, and the interaction of high speed inflow with vortices were found in the pictures among the characteristic flow patterns in the wall region.

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A tracer was developed to visualize the diffusion process of the soiled water discharged from the bottom of a hopper dredger in a towing tank.
Comparative tests on several candidate tracers were conducted to select a tracer most suitable for this kind of visualization tests within the restrictions imposed on the tests in towing tank. As the results, the mixture of microscopic particles and water was chosen, which was obtained by filtering a red-colored soil with 100 μm mesh and adjusted to the specific gravity of 1.05.
By using this tracer, diffusion process of discharged soiled water, namely the flow of the discharged soild water along the ship hull and accelerated by the propeller into its race and widely diffused, was successfully visualized. This tracer was shown to be useful for visualizing the macroscopic turbulent flow around the stern part of ship models.

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THe process of generation of turbulence in oscillatory boundary layer was elucidated by flow visualization technique and compared with the results of hot-film measurement. For the flow visualization the bed of water tunnel was covered by a thin layer of milk with specific gravity 1.015(Thin layered milk method). The thickness of the layer was about 1mm. The piston-stoke was started from rest to a sinusoidal movement. The movement of milk was recorded photographically with a motor-driven camera set stationary above the tunnel. Photographs show turbulence bursts occur in each cycle of oscillatory flow which bursts are followed by the relaminarization during the same cycle.

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This paper presents the net value of extracted wave energy by pendulum type absorber.
Test results indicate us that the wave energy depends considerably on the depth of wave generated point.
This fact has ever been unclear on behalf of the tiny amplitude theory, and then it is most important for us to establish new role by detailed obseravation of water particle moton for the purpose of estimating exact value of coastal sea wave energy.

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A new photographic technique has been used, in which a still camera, or a cinecamera with standard speeds, can be successfully used to photograph the rapid changes of breaking wind-wave surfaces. This photographic technique is an overlapping photographing technique which uses multiple strobes, flashing one after another at short intervals through optical filters of different colors. Using this technique, images of splashing droplets or of micro-scale configurations of wave surface at different instants are photographed in one picture, and the time sequences between the overlapping exposed images can be easily determined by their colors. This technique can also be used for comparative precise measurements of velocity vectors of fluid particles, including tracer particles in the air flow visualization over the waves.

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The wakes behind the ring are studied by means of flow visualization techniques.
It is found that the stable arrangement of the double row of vortex rings on a common axis of symmetry exists. The configutation of the vortex rings is different from that of the two-dimensional Karman vortex street.

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The thermal convection in the large water body has not yet clarified sufficiently. In this paper the development of convection is visualized by means of the Schlieren method, the dye injecting method, the aluminium powder method and so on. At the beginning of convection many polygonal patterns appear on the bottom plate and vortex rings appear from the vertexes of them.
The nature of convection in an equilibrium state is classified into two regions, according to the Rayleigh number, or the Reynolds number in a strict sence. In the region where the flux type Rayleigh number is smaller than 2×10⁵, the convection is in a turbulent state. but where the Rayleigh number is larger than 2×10⁶, the convection is a turbulent state.
By photographs obtained with the use of the vertical slit beam and the horizontal slit beam, relations between the convection and the external parameters are derived.

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The flow visualization technique has the advantage of displaying the whole flow field at one time whether steady or unsteady. In this study, Kármán vortex flow past a circular cylinder at Re=100 is made visible by means of tracer method in order to obtain instantaneous velocity vector distributions. A large number of tracer paths on photographs are processed by the use of a digitizing tablet whose output signals are put into the micro computer system. The computer calculates mesh point velocity vectors as well as stream function, vorticity, and pressure values after the method used in numerical experiments. All the results are presented on the CRT display in the form of contour lines. Some consideration is made as to vortex development and dissipation behind a cylinder.

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For the purpose of visualization and measurement of the intracardiac blood flow, contrast cardiotomography which is a method of recording simultaneously the intracardiac blood flow and cross section pictures of the heart in dynamic status by using the ultrasonic pulse reflection technique is investigated. From the fundamental experiment, it is confirmed that saline is the most suitalbe material for producing the artificial contrast echoes in the blood because it differs in acoustic impedance from the blood and is harmless fo patients.
In clinical application of this method, about 10 to 15 cc of saline is injected into the cardiac chambers through the catheter or a peripheral rein which a ultrasonic cardiotomogram is continuously displayed on the CRT screen by a high speed sector scanning. Artificial echoes are produced in the cardiac chambers just after injection of the saline and flow together with the intracardiac blood stream. Thus we can easily determine the direction, flowing status, and timing of the occurrence of an abnormal flow in the cardiac chambers in such cases with a regurgitant flow in valvular diseases and with a shunt flow in congenital heart diseases.
Furthermore, according to this method utilizing the M-mode, the direction and flowing status such as eddy or jet can be identified by the echo pattern in more details. Also the flow velocity can be determined by measuring the inclination of the M-mode pattern.

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New technique visualize streamlines around a body is devloped by use of Collins's streaklines. When a sphere penetrates a free surface of glycerol in a vessel, the sphere surface is coated with a thin layer of the water-laden glycerol. During the subsequent falling-motion in glycerol this layer is progressively stripped from the sphere surface to form the streakline. The streakline has a refractive index different from that of the surrounding glycerol. When an adequate numbers of spheres are released along a line vertical to the gravitational direction, a row of streaklines are formed. After then a test body is fallen in the field. These streaklines move with the surrounding glycerol according as the movement of the test body. For a steady motion the streaklines coincide with the streamlines. Therefore when a photograph is taken for the field, it show the streamlines of the uniform flow past a fixed body at this moment. The application of this technique to visualize streamlines around a solid sphere and a sperical gas-bubble reveals that the solutions for the Oseen equations represent the streamlines most accurately at a low Reynolds number below 0.4.

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Lithting with stroboscopes are used for the hydrogen bubble technique to determine the instantaneous velocity field of the two-layered flow. The stroboscopes light simultanously, at constant frequency, 2 or 3 times while the camera shutter is opened. Such, 2 or 3 images of the same moving time lines of hydrogen bubbles are taken on each photograph. During the measurement of the velocities the interfacial waves of the flow are visualized with fluorescin dye. This method is recognized to be useful to detemine the relation between the spatial distribution of the velocities and their turbulent fluctuations and the interfacial waves of the two-layered flow.

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An application of hydrogen bubble technique and a simplified electrolytic precipitation method are proposed. These methods make it possible to visualize streaklines from unstready boundary layer near the separation point on the surface of a circular cylinder which is started impulsively in still water. The physical meaning of visualized streaklines is made clear in relation to the vorticity distribution which is estimated from the velocity field obtained by conventional hydrogen bubble technique. These methods are found useful to investigate the mechanism of convective transfer of vorticity produced on the surface of the cylinder.

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The aim of this research is to rationalize the prouduction methods of the duct branch and the investigation was performed at the point of loss of branch.
Six kinds of branch type were used for the testand the flow rate of the branched flow to the main flow was set to 1/2.
The pressure distributions along the flow direction were measured using Pitot tubes and inclined manometer.
The results of these research shows that the branch Type2 is fitted to the purpose of rationalization.

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By applying a smoke-wire method, the air swirl in a diesel engine cylinder was visualized successfully in the condition of motoring. The specially designed single cylinder engine used has an observation window on the top surface of piston. The smoke-wire was made of 4 intertwisted nichrome wires each with a diameter of 0.17mm and set up near the cylinder head and nearly in the direction of cylinder diameter, and was coated with glycerin. This cylinder part (15mm thick) was made transparent. The smoke was illuminated from the flank and taken photograph from bellow the piston using a reflex mirror and a high speed camera. The capacity of discharge condenser was 1500μF and the charge voltage was 250 volts d.c.

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The behavior of the two-dimensional periodic disturbances introduced into turbulent boundary layers is determined by means of the smoke wire method. It is found that (1)the disturbances whose wave number is between about 0.1 and 0.6 are amplified in the downstream direction (the wave number is 2πδ^*/λ, where δ^* is the displacement thickness and λ the wavelength), (2)the disturbances whose wave number is about 0.3 are amplified most strongly, and (3) the disturbances whose wave number is larger than about 0.6 are damped. The present experiments strongly suggest that the large scale coherent motion originates in the instability of the mean flow.

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