The Cross flow patterns, the total pressure losses, the vorticity and drag distributions of the wakes of 1/5 car models are visualized by combining three 5-hole picot tubes and a traverser in a wind tunnel. Three, passenger car shapes, an original one, the one with a reduced rear window angle, and the one with a rear spoiler, are examined and the wake data are obtained in the cross section at a half car length downstream from the car rear end. These data are calculated to evaluate vorticities, drag values, and so on and are presented as color contour maps.
The results show that in the case with the spoiler the vortices generated from rear pillars don't become clear and rather rotate in reverse, and the reduced rear window angle weakens the vorticity up to half of the original value. Using the drag distribution maps, we will be able to find out the body shapes which generate large drags.

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The present paper discribes a result of flow observation around bow of the high-speed fine ship which has V-shape transverse section with knuckle corners at bottom. The so-called milk-painting method is used for the flow visualization of limiting stream-line and separated vortex flow.
As the resutlt of flow visualization, it is observed that the longitudinal vortex caused on 3-D separation exist around bow in oblique flow. Investigating the position of the vortex core to refer the results of velocity distribution measurment, it is different from one of the low-speed full ship, consequently.

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Characteristics of flow fields around a ship model moving obliquely in shallow water are investigated by a flow-visualization technique using the dye tracer method. This report gives observed results for inclination of the trailing vortices with respect to a ship hull, streamlines on the hull surface and directions of flows behind the stern.
As a result, it is clarified that the inclination of the trailing vortices is remarkably dependent on water depth. This result for a flat plate wing agrees qualitatively with the theoretical value determined on a base of Bollay's wing theory. Additionally, it is indicated that the water depth has considerable influence on flow-straightening effect of a ship body.

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This peper deals with fundamental aspects of delaying tip vortex cavitation on a propeller by the artificially roughened tip. The flow visualization on propeller blades by the oil-film method and measurement of static-pressure for the inception of tip vortex cavitation are conducted in I.H.I. cavitation tunnel. We can get some of the aspects of the tip vortex roll-up proccess from the flow visualization, and the results of the measurement indicate substantial decrease in the static-pressure for the inception of tip vortex cavitation by the roughness. An prediction method for tip vortex inception is developed by modifying McCormick's model of tip vortex, and compared with the experiments conducted by Souders et al.

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Steady and quasi-steady behaviors of flows in the mixed-compression supersonic intake are visualized by using the schlieren photograph. local vapor screen method and surface oil flow method. Structures of shock wave with schlieren photograph are presented herein. Tests were done at the mach number from 1.5 to 3.0. The results show that the outline of basic flow structure affected with back pressure and air bleed effects have been proved. Especially, the visualized shock patterns of near throat regions are observed to behighly complicated, which are associated with shock boundary layer interaction.

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Supersonic air-intake is one of the most important components to realize the supersonic/hypersonic air-breathing engines. A mach 3 intake was designed and tested with the supersonic wind tunnel. In this study, several flow visualization methods such as schlieren photograph, oil-flow and vapor screen methods, were applied. Here, the results with vapor-screen method using acetone and pentane were presented. The boundary layer flow changes, associated with the back pressure controlled by the flow plug, were visualized clearly. The secondary flows and vortices were also caught.

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Some experimental and numerical visualizations have been made on the starting flows past a two-dimensional airfoil oscillating in pitch at large incidences. The model airfoil, ellipse or NACA 0012 in cross section, is set in motion impulsively and subjected simultaneously to a steady translation and a harmonic oscillation around the pitching axis situated at mid-chord. The Reynolds number based on the chord length is fixed at 3000 and the reduced frequency ranges between 0.1 and 1.0. The mean incidence and the angular amplitude are provided two varied values.

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The purpose of this study is to investigate the relation between behavior of a flexible wing with pitching motion and the mechanism of a thrust generated by the wing. Flow patterns around the wing are visualized using a dye-injection method and filmed with a high speed video camera.
It is shown that the flexible wings have several modes of vibration corresponding to the frequencies, and the generation of flow separations and the vortex formation on the hollow of the wing curved influence a thrust of the flexible wing oscillating.

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There are many applications of selective withdrawal in engineering and environmental fluid mechanics. This paper presents flow structure in water bodies induced by selective withdrawal from two-dimensional and two-layered systems. The flow structure is investigated experimentally by flow visualization, using dye solution and shadowgraph method, for surface withdrawal and bottom withdrawal case.
In the case of super critical withdrawal, the experimental results shows the viscous effects is negligible and flow structure is quite simple. On the other hand, complicated flow structure and intermittent outflow accompanied with spiral shape vortex are visualized when discharge of withdrawal is almost critical condition. Growing vortex in the ambient water due to viscous effect which appears when the discharge of withdrawal is less than critical condition is also visualized and reported that it cause the formation of the middle layer which defined density distribution.

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Flow patterns in a symmetrical two-dimensional wavy-walled channel were investigated at low Reynolds numbers: 10-300. In the case of steady flow, we observed a new flow structure consisting of a regular three-dimensional flow as the Reynolds number exceeds 27.5. In the case of oscillatory flow, the Reynolds number for transition from two-dimensional flow to three-dimensional flow increases with the Strouhal number.

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The coherent structure of turbulent meandering flow is investigated using the technique which visualize both streamwise and side views simultaneously by fluorescent dye injection method.
The lifting "wall streamwise vortices" on "dye transport pattern", which is a large scale cohrent structure of turbulent meandering flow, are observed by streamwise and side views. It seems that these vortices are caused by the interaction between high speed fluid and large scale vortices near side wall.

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The behavior of plumes in stably stratified fluid layers is experimentally studied using the flow visualization techniques.
First, flow patterns of plumes are observed and classified into the following four regimes by means of the densimetric Froude number Fd, 1) two-cell convection, 2) trans it ion, 3) steady plumes with weak convection, 4) unsteady plumes with intermittent thermals. Second, the quantitative characteristics of plumes such as the rising height, the upward velocity etc. are investigated. As a result, it is found that the quantitative characteristics depend not only on the densimetric Froude number Fd but also on the parameter ε which expresses the strength of the nonlinearity.

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The natural convection of water in vertical narrow annural gaps is visualized by using polystirene particles and temperature distributions of a inner wall are measured. The present study shows mainly flow patterns during unsteady state. Several local circulating flows occur near the high temperature surface after a few minutes of heat beginning and that flows combine and large circulating flow occurs. The two pair of circulating flows are formed along the circumferential and vertical direction with the passage of time and change one pair after the long time.

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Experimental study was conducted in the flow field of a clean room subject to a clean room fire. The counter-flow which was caused by downward flow and upward current from a model fire source was visualized using two kinds of smoke. A pointt source or a Iine fire source was adopted as a model fire source. respectively.
While the buoyancy force depends on the heat release rate. hot current which included smoke from the model fire source rose against down flow and reached at least 2m height in this experiment. This updraft current upon contacting the down flow was observed to form an umbrella shape. Most of the air. floor and walls in the clean room were contaminated with combustion particles within a few seconds.

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The characteristics of a rising air flow from a range with a hood fan in a kitchen are studied. The followings are clarified.
(1) The updraft from a range is clearly visualized.
(2) The air flow distribution above a range is characterized by a clear updraft from the range.
(3) When the power of a range is 2.5kw, the capture ratio of the steamy exhaust gas from a pot or a kettle on the range by the hood is 100% if the total exhaust air volume exceeds 300m ³/h.

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To make a good cabin air conditioning of the vehicle it's need sometimes to know about the air flow in it. This paper reports about the example to have approached to know it with the methods of tuft stick grid and numerical simulation.
As the result we've recognized that we could easily visualize the air flow of cabin interior with tuft stick grid. And also it's effective to calculate the 3-D model to know more details.

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A new velocity measurement system has been developed which uses the image processing techniqpues as well as the numerical. In the present method, two-dimensional plane velocity distributions on several scanned planes are determined by digitizing the paths of hydrogen bubbles which are visualized by the laser sheet beam. Then the three-dimensional flow fields are reproduced numerically for the plane velocity distributions to satisfy the continuity condition. A feasibility application is made to measure the wake flow behind a Wigley ship hull.

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A new algorithm of three-dimensional particle tracking has been developed to increase the number of velocity vectors obtained by the particle tracking velocimeter (Nishino et. al., 1989). This algorithm utilizes four consecutive sets of image data to establish both spatial and temporal correspondence of identical tracer particles. In the measurements of a homogeneous isotropic turbulence and a 2-D turbulent channel flow, it is demonstrated that the present algorithm works quite effectively in increasing the number of vectors and that as many as 441 instantaneous velocity vectors are obtained in the latter measurement.

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A fully-developed two-dimensional turbulent channel flow has been measured using the three-dimensional particle tracking velocimeter based on a digital image processing technique. Turbulence intensities of all the three velocity components as well as the Reynolds stress were obtained well into the viscous sublayer from a total of 4.37 million velocity vectors. Present results show excellent agreement with those of the direct numerical simulation by Kim et al. (1987). In contrast to these results, the well-known near-wall data measured with the hot-film probes (Kreplin and Eckelmann, 1979), show considerably higher values of the wall-normal and spanwise turbulence components in the region of y+ ?? 20.

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The 3-D particle tracking velocimeter was applied to the detailed turbulence measurement in a flow downstream of the one-side expansion of a two-dimensional channel. The mean velocities as well as the second-order statistics of three turbulence components, which will be useful in evaluating various turbulence models, have been calculated from about 2x106 measured instantaneous velocity vectors. Based upon the analysis of the forward-flow fraction, the mean reattachment length is determined as (7.0±0.5) times the step height. The anisotropy measures of turbulence components show that the spanwise velocity fluctuation is the largest near the wall in the reattaching region unlike the equilibrium wall-layer turbulence. This fact must be properly taken into account in numerical predictions of turbulent separated and reattaching flows.

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In this paper we report the results of flow visualization by means of aluminum dust method, hydrogen bubbles method and dye injection method for the constricted pipe flow at the rear of stenosis. The experiments were carried out under some steady flow rate conditions.
The results may be summarized as follows: The flow-field is divided into jet region and recirculation region. The change of the structure is closely related to the change of Reynolds number. In the jet, the existence of potential core and orderly vortex structure is observed to be dependent on Reynolds number. The process of vortex formation, grow-th, coalescene and breakdown affects the reattachment length in jet.

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Liquid flow in a co-axial cylindrical viscometer was visualized using markers in water. Taylor vortices were observed over the critical rotational speed, in which the value of viscosity or torque began to increase apparently. Especially by the enlarged cross-sectional visualization using a microscope and a VTR, it was recognized that a flow pattern of the vortex did not lead to a square cons-section but to a rectanguler one.

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The effect of addition of 1-octanol on the interfacial turbulence during the absorption of steam by LiBr solutions was studied experimentally using schlieren method. In the experiment, the steam was absorbed into a quiescent liquid pool of LiBr solutions, and the liquid flows near the interface were observed by a video camera. It was found that the interfacial turblence is induced by Marangoni effect and that the mechanism can be explained by the dependency of surface tension on the concentration of LiBr and 1-octanol in the liquid phase.

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The breaking process of the K-H wave in an unsteady exchange flow is investi-gated through the experiment by using a simple visualization technique. Two-dimensional vortex pairing, convective rolles and knots which are mentioned by S.A. Thorpe as transitional phenomena of turbulence in stratified fluids are con-firmed in the flow of the low Richardson number. On the other hand, the flow condition of the high Richardson number brings several uninvestigated three-dimensional breaking process.

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A motion graphic technique was utilized to visualize some computed flows around automobiles. Multi-block transformation and transfinite interpolation were used to generate the complicated grid systems. Unsteady flow fields were computed by the finite difference method using a third order upwind scheme. A mini supercomputer and a graphic work station, which were connected with each other through a local area network, were used for the grid generation and the flow visualization.
It is concluded that the combination of the multi-block grid generation and the motion graphic flow visualization is very useful to analyze the unsteady flow. It enables us to understand the flows around the realistic automobile shapes with wheels, wheel wells and mud guards.

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A technique to obtain flow vector mapping through stream function evaluated from two-dimensional ultrasonic Doppler information is proposed. Medical ultrasonic systems for two-dimensional Doppler flow mapping are commercially available, so the two-dimensional Doppler information on a flow can be obtained in real time. A technique that deduces a flow vector mapping from the Doppler information about a fluid flow was therefore developed to evaluate cardiac function quantitatively. This technique can be applied for the observation by the Doppler effect of a fluid of scattering light or electromagnetic wave.

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Flows past a circular cylinder is a classical problem of the fluid mechanics and it is well known that the Karman vortices disappear when the rotating speed is large. But the dependence of this phenomenon on the Reynolds number of the flow has not been recognized. We simulate this phenomenon by the discrete vortex method and compare the flow field to that obtained by the hydrogen bubble method.

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Two-dimensional discrete vortex method is applied to the flow at an open-channel confluence. Mean and turbulent velocity characteristics together with the size of a recirculating region are calculated with a reasonable accuracy and compared with open-channel experimental results. Also, unsteady large scale struc-ture of the flow in the recirculating region including formation and decomposition of vortices is favorably simulated by the proposed model.

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In the previous report, velocity vectors and vorticity contours of an unsteady viscous diffusing free doublet flow field were analyzed using a digital image processing system based on the correlation method. In it a serious problem was pointed out oncerning the identification of the tracers using the correlation method for the flow patterns with sharp gradients of velocity and great vorticity. The purpose of the present study is to propose a quantitative limit of the applicability of the digital image processing system using the correlation method. Some experimental simulations were carried out employing the analytical solution of the same doublet flow field as a flow model. The effects of the correlation region size on the erroneous vectors due to the sharp gradient of velocity and great vorticity were discussed in detail.

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The ventricular assist device (VAD) should supply the wide range of the flow assistance according to the cardiac requirement after the failing natuaral heart. The flow behavior within our different several types of VADs had been analized with the numerical method based on the flow visualization technique. In this study, it was observed that the stagnation in which the thrombus would be generated was affected mainly by the contour of VAD. According to the results of the flow. characteristics within VADs, the contour of the junctions between the sac and the inflow and outflow tracts were improved to the smooth configuration which enhanced the rotating flow in the diastole and minimized the stagnant area within the sac. It was concluded that the flow visualization furnished the very useful information on the development of the VAD.

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A computer aided flow visualization of the outstripping and collision between a pair of vortex rings which are the same, was done by using a personal computer. The three-dimensional vortex method was used and a Rankine's vortex which is combined with a free vortex outside of the core and a forced vortex inside of the core was introduced. It is difficult to observe the behavior of the flow caused by the interaction between a pair of vortex rings by the experimental method. Therefore, this computer aided flow visualization is especially varid for the oblique collision of a pair of vortex rings. As a result, the interations between a pair of vortex rings were well described by this method.

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The flow in and above the flexible roughness was explored with the computer simulation using MAC method. In this flow the instability was found at a low frequency region as well in a mixing layer. And then, the above computer simulation was carried out with the in-flow boundary condition given by the velocity data of the wind tunnel experiment. The streak lines obtained with the computer simulation were compared with those by the smoke wire method of the wind tunnel experiment. The vorticity distributions changed every time were also illustrated.

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Fluctuations of flow parameters in a jet are generated in the shear layer of the jet boundary as the backpressure is increased. To investigate fluctuations, it is desirable to perform experiments with nonintrusive diagnostic methods. In the present experiments, the laser-induced fluorescence method was used to measure the fluctuations of a low-density axisymmetric argon jet with high spatial and temporal resolution. With this technique, the critical Reynolds number above which fluctuations were generated in the shear layer was obtained, and the fluctuation distribution of the fluorescence intensity in the jet was also clarified.

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Visualization and measurements of the velocity field in a pulsatile flow through a branching tube of square cross section with 45 degree take-off angle from the parent tube was made using a laser induced fluorescence method. Velocity profiles in two directions across the duct at eight different phases in a period of the pulsation were visualized at 24 different cross sections. As a result, at the parnet tube, the velocity profile was similar to that in a straight duct throughout the period of pulsation. At the branching portion, a vortex developed at the deceleration phase of pulsation near the outer wall side of the branch and it disappeared at the acceleration phase. At the downstream of the branching poration, flat velocity profiles were observed in both daughter tubes throughout the period of pulsation.

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A holographic visualization of the pressure on the plate impinged by an axisymmetric turbulent air jet and reattached by a backward step flow have been carried out. A subdived silicon rubber sheet located on a plate was transformed with a pressure and its distrubution was measured by realtime holography. Fringe patterns indicate only pressure fluctuations when the plate image deformed by a pressure is used as original image. These were clarified by this method that axisymmetric coherent structures existed in the jet simultaneously and there were various coherent structures. Turburent structures above two regions are investigated again quantitively with the cross correlation between the pressure fluctuation on the wall and the velocity fluctuation at various points in flow. The movement and collapse of a large eddy are traced from the contours of cross correlation, which show that a large eddy impinges and passes away on the plate.

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The wake flow behind a road vehicle is visualized by the lazer light sheet method. The results are compared with the total pressure distributions in the wake and the flow patterns clarified by the fluorescent taft grid method. The effects of blockaged test section and rear body shapes are discussed, and the physical meanings of the visualized patterns are also considered.

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The flow around a circular cylinder or a rectangular column placed at various spacing to a flat plate has been investigated experimentally by making use of visualization technique. An open channel is used for the experiment, and the column is placed vertically to the bed. The method of flow visualization used in this report is the beam sweep laser speckle photography. The plane of observation is illuminated by periodical sweeps of a laser beam scanned by a galvanometer mirror, and multi-exposure photographs of speckle pattern of the flow seeded with tracer particles are recorded.
Visualization results clearly show the change of horseshoe vortex system with the spacing between the end face of column and the bed of the channel.

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The Laser Speckle Velocimetry (LSV) is one of the most useful method of quantitative flow visualization, because it gives two-dimensional instantanious velocity distributions. But this method is not suitable for continuous measurement of unsteady flow, because normally the repetition rate of pulse laser is low.
We have reported a new illumination technique by making use of CW laser, and named the Beam-Sweep Laser Speckle Velocimetry (BS-LSV). A plane of observation in a flow field seeded with tracer particles is illuminated by periodical one-way sweeps of a laser beam instead of pulsed light sheets. This method is suitable for measurements of an unsteady flow, because the sequential specklegrams can easily be recorded continuously.
In this report, BS-LSV is applied to two-dimensional velocity measurements and visualization of pulsating flow in a peristaltic pump.

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A basic knowlege for laser speckle photography (LSP) and in-line holographic interferometry is highly essential to obtain two-dimensional velocity distribution of particle jet impinged by the nozzle. LSP can measure the velocity distribution for the entire impinging field. However it is rather difficult to apply this LSP for the high-speed or unsteady flow using CW lasers like Ar-ion or He-Ne gas lasers with the optical chopper due to the intensity of palusive laser light.
From this point of view the effort was made to obtain two dimentional velocity field of high-speed particle jet by the giant double pulsed ruby laser in this paper. It is clarified from the results that LSP using double pulsed laser can be masured with high accuracy in the renge of 51-10(m/sec). Parallel with this LSP method, double pulsed holographic interferometry technice is also carried out in order to visualize the two dimensional velocity field of particle, jet. This result agree well with the ones obtained by the LSP method. Through these total considerations, this LSP method is proved to be highly effective for the flow mesurement in a high speed particle jet.

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Holographic interferometry has been applied to the visualization of shock wave. In previous studies done by the authors, double pulsed holographic interferometry with diffused light was proved to visualize the shock wave 3-dimensionally which was formed in turbo machines rotating with supersonic speed.
As the application of this method, this paper describes 3-dimensional visualization of shock wave using the diffused light which reflects by the mirror placed behind the test section where the shock wave is generated. This reflective type can be applicable more widely compared with the transmission type. The shock waves generated at U-shaped pin which is flying counter to the supersonic flow is recorded on hologram by this method. As the result, the reconstructed image enable us to understand the 3-dimensional shock wave configuration at the edge of U-shaped pin.

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The authors have been studied visualization and analysis methods of electrostatic fields. In this paper an electric field with space charges is simulated by a fluid mapper with a fixed sand-bed which behaves as distributed sources or sinks of fluid flow. The fluid mapper method visualizes the lines of electric force in axisymmetric three dimensional fields satisfied with Poisson's equation. Moreover, the equi-potential surfaces in the electric fields are represented graphically by a flow pattern from this method. Finally the experimental results of this method show that the justification of numerical results calculated by the computers can be inspected by the flow patterns.

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The authors focus the mechanism between breakdown stress and polarities of accumulated electric charges along the surface of conical spacers applied D.C. voltage, and analyzed the quantitative influence of the accumulated charges along the surface to D.C. creeping breakdown characteristics. They also discuss polarity effects of the accumulated charges along the surface by using a surface electrometer and dust figure method, and visually analyzed electric fields of the conical spacer periphery by fluid flow mapper equipments in this paper. The justification of the estimated values of the accumulated charges is inspected by the fluid flow mapp.er equipment. Finally, It is emphasized that relaxation phenomena of the electric field arising in the triple-junction of the spacer surface is visualized and analyzed by the fluid flow mapper in this paper.

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This paper presents an experimental study on impingement of two turbulent plane free jets. Flow visualization by dry-ice vaporing method, the effects of impinging angle and velocity ratio on the concentration were investigated. As a result of this study, it is found that the mass transfer differs from the momentum transfer slightly and the concentration distributions are not similer as yet.

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For the purpose of non-invasive quantitative evaluation of the intracardiac blood flow dynamics, a new method for obtaining the stream lines and velocity vector distribution of the blood flow has been developed in our laboratory. In this study, characteristics of intracardiac flow were investigated in normals and several cases with myocardial infarction by using this method. Flow velocity data were obtained from ca 150 sampling points on the apical long axis cross section plane of the heart by the use of pulsed Doppler method of 3.5 MHZ ultrasound. The stream lines and velocity vector distribution were calculated from the 2-dimensional distribution data of the velocity by applying the stream function theory. From the 2-dimensional distribution of the stream line and velocity vectors, the flow speed and direction are clearly evaluated.And spreading or gathering flow, rotating flow are eddies in the ventricle occurred during one cardiac cycle are also estimated. From the results obtained from the pathological cases, it is considered that the flow state and dynamics reflect the changes in local myocardial contractibility and extensibility and that this new method will serve as a useful and reliable technique for evaluating the intraventricular flow dynamics and myocardial functions.

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The size of micro particles suspended in fluid and the velocity of fluid flow are measured by the counting method of the photon of the scattered light from fluid.

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This paper described a new visualizing method of streamlines around a body in hypersonic flows. The visualization of a streamline around a wedge was tried and the visualized result was compared with the theoretical wedge flow in order to verify the usefulness of the result obtained by the present method. From this comparison, it was proved that the present visualizing method is available for the visualization of streamlines around hypersonic vehicles. Moreover, the visualization of a streamline around a hypersonic wedge with an afterbody of a rectangule was performed by the present method, successfully.

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An experimental study has been performed to investigate the influence of density inversion of water on free convection and temperature-distribution characteristics of air-water layers within a cooled circular tube. The experiments were carried out under the condition that the tube-wall temperature was favorably decreased at a uniform rate. A holographic interferometry technique was adopted to determine the time-dependent distributions of the temperature in the tube. It was observed that the temperature-distribution behavior varied to a great extent due to the cooling rate of the tube wall based on the time-dependent sequential flow pattern. The heat-transfer characteristics along the tube wall were also extensively determined. It was found that there were three peculiar dendritic-ice formations within the water layer of the horizontal tube based on the cooling rate.

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Two-dimensional temperature distribution of a heated flat plane with a perforated cylindrical promotor through a plastic permeable wall is visualized by using coated thermosensitive liquid crystal and the infrared radiation sensor. Thermoview of the base plane is obtained by these methods. Heat transfer augmentation effect arround a promotor is quantitatively studied by the remote sensing radiometer.

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In order to reduce the erroneous vectors which appear in image processing system for automatic measurement of flow fields with high vorticity and shearing strain rate and to ensure the measurement precision which is affected mainly by the digital sampling errors, a numerical simulation was executed using an elementary solution of two dimensional Oseen's equation as a flow model, which corresponds to the unsteady viscous diffusing free doublet flow. Four effects of vorticty and shearing strain rate, subregion size, tracer size, and interval between two pictures on erroneous vectors were investigated, and a quantitative estimation of sampling errors was proposed based on the simulation analysis.

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