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Yoshiro Kimbara
1993 Volume 13 Issue Supplement2 Pages
1
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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Taketoshi OKUNO, Nobuaki KIMOTO
1993 Volume 13 Issue Supplement2 Pages
3-8
Published: October 01, 1993
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Several image measurement methods for obtaining time-mean velocity field are investigated. The spatial filter method and the time-averaged contrast method, which have been reported already by the authors, are examined again for comparison of techniques. A new method, called zero-cross counting method here, is also proposed. Algorithm of the present technique is very simple using only difference betweeen images and its accumulation. This is effective to measure a slow velocity.
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Junichi OHTA, Fujio YAMAMOTO, Mitsuo KOUKAWA
1993 Volume 13 Issue Supplement2 Pages
9-12
Published: October 01, 1993
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It has been desired to measure a velocity field around bubbles and bubble shapes in a liquid flow in order to clarify flow characteristics of a gas-liquid two-phase flow. Thus, a velocity field around a bubble flowing in water and the bubble shape were simultaneously measured. The bubbly flow was formed to pump air into water flowing upward in a rectangular duct ( 60×30 mm). Binary image correlation method based on high speed images between 1/200 sec was applied to measure the liquid velocity field around the bubble. The bubble shapes for the same high speed images were measured by a X-Y coordinator. The measured velocity field overlapped with the bubble shape are presented.
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Kohtaro OHBA, Hitoshi SOYAMA, Sho TAKEDA, Tadashi ISHIHARA, Hikaru INO ...
1993 Volume 13 Issue Supplement2 Pages
13-18
Published: October 01, 1993
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In order to clarify the mechanism of the severe erosion mainly resulted by the singular vortex cavitation, we carefully try to observe the vortex cavitation associated with the erosion around a butterfly valve by means of a high-speed video-camera, whose framing rate is 40500 per seconds. The velocity of cavitating flow are measured by using the digital-image processing-technique. It is worth noticing that the vortex cavitation develops in the boundary region between the main flow region, i.e., the orifice-jet, and the recircurating region. The cavitating vortex core consists of several tiny vortex cavitation. And the rotating velocity of the highly erosive vortex cavitation can be also detected by the technique.
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Hidemi YAMADA
1993 Volume 13 Issue Supplement2 Pages
19-22
Published: October 01, 1993
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The quantitative analysis of a horse-shoe vortex upstream a rectangular plate protuberance standing vertically on a flat ground wall, where the laminar boundary layer develops, was attempted by using a image processing based on spatio-temporal correlation against the visualized particle image. In this image processing method, the velocity vector can be measured by using eight time-lags which are obtained from the time-correlations between a center pixel and each neighboring pixel. This method must employ the time sequential image. But the processing domain for analysis may be smallest among many correlation methods. Therefore, this method was applied to the measurement of velocity and vorticity distributions in the steady flow field which the laminar horse-shoe vortex was formed.
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Nobuyuki FUJISAWA, Yoshikazu TAGUCHI
1993 Volume 13 Issue Supplement2 Pages
23-28
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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The flow field in a rotating Savonius rotor is measured by particle-tracking velocimetry with conditional sampling technique and is compared with the streak-line pictures visualized by smoke-wire method. The present measurement reproduces well the qualitative nature of the flow field in and around the rotor observed in the streak-line pictures. It is also found that the flow velocity on the advancing blade side is increased with a growth of tip-speed ratio, which is enhanced at small rotor angles by the presence of the Coanda-like flow pattern on the advancing blade. The flow phenomena such as the separation on the convex side of the advancing blade, vortical structure inside the rotor and the development of the wake downstream are clearly indicated in the present velocity-vector diagrams.
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T. KOBAYASHI, T. SAGA, T. SEGAWA, Y. KOBAYASHI, T. WADA, Y. SHINDHO, R ...
1993 Volume 13 Issue Supplement2 Pages
29-34
Published: October 01, 1993
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To create the comfortable ventilation in a room, the low flow speed ventilation to the ceiling has been investigated. The air flows in a model room and the natural convection around a human body were visualized by a smoke method and a technique of laser light sheet. Quantitative full-field velocity measurements were carried out by analyzing the flow visualization images by using a simplified density correlation method. At the same time, the CO2 concentration and the temperature distribution in the room were measured. The results indicated that the low speed ventilation air supplied to the ceiling is circulated in the whole region of the room, and a good air condition in the room can be performed under the appropriate ventilating condition. It was also found that the influence of the upward natural convection due to the human body was an important factor in the ventilation design.
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Hirotoshi FUJIEDA, Toshimi FUJITA, Akihito IWASAKI, Hitoshi TAKAHASHI, ...
1993 Volume 13 Issue Supplement2 Pages
35-38
Published: October 01, 1993
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The aircraft employing the Upper Surface Blowing(USB) system as a poweredlift technology makes use of the energy of the engine exhoust to augument wing lift. The aircraft with the USB system achieves higher powered-lift by turning full downward the engine exhaust flow. To studying powered-lift characteristics, the wakes of the semi-span aircraft model with USB Powered high lift system were measured by a taversing wake rake with 5-pitot tube in NAL 2×2m Gust Wind Tunnel.
In this report, the characteristics for the wake having different turning angle of exhaust flow are described.
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Tosihiko IKEDA, Yoshiaki TSUCHIYA, Tadanobu KUBO, Tyozi HORIKOSI
1993 Volume 13 Issue Supplement2 Pages
39-42
Published: October 01, 1993
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It is well known that a pair of vortices is formed in the shear layer of unsteady jets. In this experiment, the vortex behaviour due to the difference of the nozzle shape (the difference of the length of the parallel section of the nozzle) has been investigated using the electroytic precipitation method and the hydrogen bubble method. It is found that the vortex moves faster when the parallel section of the nozzle is long than when it is short.
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Tadanobu KUBO, Toshihiko IKEDA, Yoshiaki TSUCHIYA
1993 Volume 13 Issue Supplement2 Pages
43-46
Published: October 01, 1993
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Inner flow of two kinds of circular cylinders is investigated by using hydrogen bubble method. Each cylinder of one group has one suction slit and two discharge slits. Each of the other group has one suction slit and one discharge slit. Each cylinder of the latter group has a rear plate near the discharge slit.
Results of flow visualization show that the velocity of the inner flow of the tested cylinders changes variously according to the inlet flow direction. In the case of the former group, when the outer flow is directed toward discharge slit, reverse flow is observed in the cylinder. On the other hand, inner reverse flow is not observed in the latter group of the cylinder.
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Shinzaburo UMEDA, Wen-Jei YANG
1993 Volume 13 Issue Supplement2 Pages
47-52
Published: October 01, 1993
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The flow in the intersecting region of two streams inside a X-shaped flow network is complex due to combined results of the ramming phenomena and the centrifugal force induced by the flow passage geometry. In order to determine the flow mechanisms, this study applies the particle tracing method to observe streamlines and the string method to visualize flow oscillations downstream from the intersecting region. Both the symmetrical and asymmetrical flows between the two branches are investigated.
The intersecting angle and flow rates are varied to determine their effects on flow behavior. Flow oscillations in the downstream branches are found to be related to vortex formation.
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Hiroyuki KAMINO, Kenkichi OHBA, Atsushi SAKURAI
1993 Volume 13 Issue Supplement2 Pages
53-56
Published: October 01, 1993
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A laser-induced fluorescence (LIF) method was used to visualize and measure instantaneous velocity profiles in pulsatile water flow through a 180° curved circular tube (U-bend). Visualization of instantaneous velocity profiles across the tube was made at eight different phases in a period of the pulsatile flowrate waveform at the position of θ=45°. As a result, the followings were clarified: In steady flows, besides the main secondary vortex pair, additional vortex pairs appear in the inner-half central region. In pulsatile flows, the velocity profile in the core region was not altered during a period of pulsation, while the profile in the wall region oscillated. The phase of the velocity oscillation in the inner wall region was a little ahead of that in the outer wall region.
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Tadatomo KOJIMA, Jinglong YANG, Mari SHIMAZUE, Yoshihiro MATSUOKA
1993 Volume 13 Issue Supplement2 Pages
57-60
Published: October 01, 1993
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In this paper, the numerical analyses of the flow with heat transfer flow in pipe having fins were studied. The analyses were carried out for the several of combination models in the length and interval of fin over a wide range of Reynolds number. The k-ε turbulence model was chosen to calculate the velocity and temperature. The results obtainded were as follows ; (a) the temperature differences between the inlet and outlet decreased and presented distinction each other with increasing Reynolds number, (b) the pressure drag coefficient was constant approximately in each pipe, and differ greatly from each other.
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Kazuhiro MURAI, Yousuke KAWASHIMA, Shigeyasu NAKANISHI, Kazumasa USUDA ...
1993 Volume 13 Issue Supplement2 Pages
61-66
Published: October 01, 1993
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In order to investigate the combustion gas in a small scale furnace, the experiment on visualization and characteristics of temperature of natural convection flow is made in a model room and the numerical calculation is conducted. In the experiment on flow visualization and temperature in fluid, water is used as the working fluid. Flow pattern is obtained by means of the aluminum powder method. The numerical calculation based on the stream function(ψ)-vorticity(ω) method is conducted in the case of laminar flow. In the case of turbulent flow the k-ε method is applied. The similarity between the room and the practical furnace is not always established because the latter has premixed burners and around which there are some of secondary air flows. However, the fundamental feature of flow patterns is observed. The clockwise and counter clockwise circulation flow is observed alternately in the model room, and the bend of streamlines around burners is obtained as a result of the numerical simulation.
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Tsuyoshi SUGANO
1993 Volume 13 Issue Supplement2 Pages
67-70
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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Recently in the earth science, geophysical subsurface information can be visualized more easily and detailed. Electrical prospecting methods include the effective subsurface imaging such as resistivity tomography.
In order to improve the accuracy of geophysical information extraction, pragmatic visualization theory and technique have been expected. In this paper, the author try to explain an effective electrical visualization method for subsurface resistivity interpretation, which includes fundamental and preliminaly/Predictive tool and system such as the sensitivity distribution techniques.
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Makoto Taguchi, Katsuhito Yamaguchi, Akira Kondo, Nobuharu Sakai
1993 Volume 13 Issue Supplement2 Pages
71-74
Published: October 01, 1993
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Recently, many simulation are carried out for various natural phenomenon, and many obseved data are accumulated for a long time. These simulated and obseved data are enormous, so it is impossible to investigate these data without visualization.
So, we develop 3-D visualizaition system for these data. This system can display any scalar distribution (any cross section), stream using particle method and animation. In addition, this system can put displayed image on record easily.
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Yasuki Nakayama, Katsumi Aoki, Makoto Oki
1993 Volume 13 Issue Supplement2 Pages
75-78
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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It is said that the Joumon Age Culture continued 6, 000-7, 000 years since 9, 000 years ago, and the people who bore the culture is called Joumon-jin. Earthen ware that were produced by Joumon-jin are called Joumon-doki.
Joumon-doki have been discovered in various parts of Japan and there are many kinds of them. Among them, one discovered in Niigata District at the end of 1931 is very famous for its nice patterns, and it was named Kaen-doki.
The patterns on its lip and side wall are related to the water flow, the authers believe. The nice vortex patterns of Kaen-doki put on them were patterned after vortices that were observed downstream piles, rocks, etc. in a river as visualized by flowing leaves which played a role of tracer.
This fact was reproduced using the Floating Tracer Method, one of the visualization methods of modern age, and thus the process of vortex generation was cleared by utilizing the computer simulation.
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Ryozo ISHIWATA, Takashi KAWAGUCHI
1993 Volume 13 Issue Supplement2 Pages
79-82
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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It is useful in the education on fluid dynamics to show animated computer graphics for some kinds of flows, since they are dynamic phenomena. Therefore the personal computer softwares with animation have been developed in this research. It was confirmed by tests that they helped students to understand and to be interested in fluid dynamics phenomena. Sinse the computer graphics are effective to visualize clearly only a necessary subject, they are expected to be practically used for engineering education, especially for fluid dynamics.
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Visualization of Leak Flow Through a narrow Gap between Impeller and Casing Wall of Magnetically Suspended Centrifugal Pump
Teruaki AKAMATSU, Tomonori TSUKIYA
1993 Volume 13 Issue Supplement2 Pages
83-86
Published: October 01, 1993
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A wall flow trace method using micro particles has been established in order to visualize leak flow through a narrow gap between impeller and casing wall of a miniature Magnetically Suspended Centrifugal Blood Pump. The size of the gap is so narrow that the oil film method cannot be easily applied to this flow.
In this method, CaCO
3 micro particles suspended freely in water form flow patterns on the impeller disk as a result of their adherance to the impeller's surface made of alminium. The results show that the flow patterns obtained by this method are clear enough to detect the flow direction, and also that the peripheral velocity of fluid near the inlet, in some cases, is faster than that of the impeller.
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3rd Report; Visualization of exchange flow in an inclined pipe
Masaaki KAWAHASHI, Kenji HOSOI, Hiroyuki HIRAHARA, Daishun FUKUI, Moto ...
1993 Volume 13 Issue Supplement2 Pages
87-90
Published: October 01, 1993
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In the duct having a large divergence angle of square cross section, a slight difference of state of flow occured in the neighborhood of throat wall surface at the upstream inlet and in its four corners grows rapidly at the inlet of divergence duct and makes the entire flow in the duct not uniform unsteady flow. Also in the case of a rapid velocity of flow, a separation from the wall surface occurs, however, the state of separation is different in the corners and the center of wall surface. A reversed stream occurs in the place where the separation takes place. Furthermore, secondary flow occurs in the four corners.
The state of flow and the intensity of turbulence in the neighborhood of L/W=1.0 in the duct where such an unstationary, complex flow exists and its divergence angle is 12° were investigated and concluded.
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Adjacent region of L/W=1.0 in the diffuser with 2Θ=12°
Takamitsu Ohshima
1993 Volume 13 Issue Supplement2 Pages
91-94
Published: October 01, 1993
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In the duct having a large divergence angle of square cross section, a slight difference of state of flow occured in the neighborhood of throat wall surface at the upstream inlet and in its four corners grows rapidly at the inlet of divergence duct and makes the entire flow in the duct not uniform unsteady flow. Also in the case of a rapid velocity of flow, a separation from the wall surface occurs, however, the state of separation is different in the corners and the center of wall surface. A reversed stream occurs in the place where the separation takes place. Furthermore, secondary flow occurs in the four corners.
The state of flow and the intensity of turbulence in the neighborhood of L/W=1.0 in the duct where such an unstationary, complex flow exists and its divergence angle is 12° were investigated and concluded.
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Hideo KASHIMURA, Tsuyoshi YASUNOBU
1993 Volume 13 Issue Supplement2 Pages
95-98
Published: October 01, 1993
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The self induced flow oscillation occurs when an underexpanded sonic or supersonic jet impinges on an obstacle. The flow visualization using the shadowgraph method is carried out and compared with the numerical result connected with the flow field. The optical images are analyzed by the image processing system with a personal computer. The range of the oscillation as a function of the ratio of reservoir to ambient pressure is explained. The experimental results as concerns characteristic of the flow oscillation agree with the numerical calculation solved by the TVD method.
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Shigeru MATSUO, Yasushi WATANABE, Satoshi KUDO, Fumio HIGASHINO, Koji ...
1993 Volume 13 Issue Supplement2 Pages
99-102
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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In recent years, research and development activities for next generation supersonic transport are being carried out actively by the world aeronautical community. In a supersonic intake, a cavity plays a important role in the control of shock waves. The study of the supersonic internal flow with the cavity is important not only for research on industrial applications but also for basic research in gasdynamics. In the present study, the supersonic internal flow with backward facing steps and cavities were investigated experimentally in the case of the flow Mach number 1.5 at the step and cavity entrance. A schlieren optical system, and a Mach-Zehnder interferometer composed of an Argon laser (CW) as the light source with acoust-optic modurators (AOM) were used to visualize the flow.
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Takayuki YAMAMOTO, Shigeru MURATA
1993 Volume 13 Issue Supplement2 Pages
103-106
Published: October 01, 1993
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This paper provides a new Particle Image Velocimetry (PIV) with learning function by Neural Network. This method is based on the Fourier transform method and detects a special shift by using a multiple-layer Neural Network, on purpose to improve the precision of measurement. The network learns the input-output patterns in one-dimensional problem by Error Back Propagation method.
Performance test is carried out in two-dimensional problem and the test results show that the present method induces less errors for the image patterns with velocity fluctuation than the original Fourier transform method.
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Ichiro KIMURA, Yoshihiro NAKAMI
1993 Volume 13 Issue Supplement2 Pages
107-110
Published: October 01, 1993
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The velocity vectors in a flow field estimated by an image correlation method include some erroneous ones because of mismatching a tracer image pattern to another one. Accordingly, it is necessary to determine the erroneous vectors which exist in the velocity vector distribution.
This paper presents a new algorithm for determining the erroneous vectors using Genetic Algorithms. The algorithms can distinguish erroneous vectors from right ones by checking over the entire measured flow field even if the density of erroneous vectors in a flow field is high.
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Ryu-ichiro OHYAMA, Takaaki TSUKIJI, Kiyoji KANEKO
1993 Volume 13 Issue Supplement2 Pages
111-114
Published: October 01, 1993
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This paper describes the new particle tracking method taking advantage of combinatorial optimization by the genetic algorithm. The particle tracking method has been investigated to search the identical particles between two sequential flow images. It is impossible to make a small number of particle combinations in the two images, but the identical particles are speedily found by using the genetic algorithm. Since the distance between combining particles is minimized in the identical particle when time difference between the two images is very small, we can apply the distances for exploring identical particles to the fitness function of genetic algorithm. The proper fitness function has the advantage that a large number of identical particles is discovered by one image process with the genetic algorithm. The particle tracking method has been induced by solution of optimization problem for the particle combinations. In addition, the method enables us to achieve the velocity measurement of particle movement caused by electrophoresis.
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Kosei TAKEHARA, Takeharu ETOH, Kohji MICHIOKU, Masanori SHIMAZAKI
1993 Volume 13 Issue Supplement2 Pages
115-118
Published: October 01, 1993
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An automatic particle-tracking algorithm previously developed by the authors is improved for practical use and applied to measurements of velocity fields of thermal convection. The main part of the algorithm consists of the Kalman's filtering theory and the Chai-square test. The presented algorithm employs a generation method of Delaunay network to estimate initial values of velocity vectors of newly-appearing particle images in the source light sheet.
The results of measurements are compared with those by Adrian et al. by means of LDV and a theoretical prediction by the authors. It is shown that particle tracking velocimetry by the presented algorithm is applicable to measurements of flows with heat transfer.
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Akikazu KAGA, Yoshio INOUE, Katsuhito YAMAGUCHI
1993 Volume 13 Issue Supplement2 Pages
119-124
Published: October 01, 1993
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A new algorithm of pattern tracking to calculate velocity distribution from visualized flow images is proposed. In this algorithm the similarity of a pair of image fragments is estimated with the summation of gray level differences between corresponding pixels. The summation is executed in parts, and the candidates which are judged to be dissimilar through the F-inspection are abandoned successively. This algorithm is faster than the algorithms which we have proposed till now, and also gives us the reliability of calculated vectors.
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Tomomasa UEMURA, Manabu IGUCHI
1993 Volume 13 Issue Supplement2 Pages
125-130
Published: October 01, 1993
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In order to realize the high speed analysis in the incoherent high particle density PIV, further advancement in both hard and soft-ware is expected. Anticipating the introduction of a high resolution CCD camera to the PIV, such an algorithm that can analyze pictures in which particle images are frequently appear being overlapped or put together is to become necessary. The new algorithm is based on the binary-image correlation method and the velocity-vector histogram method. The analysis can be finished in practically short seconds on a personal computer.
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Takeharu ETOH, Kosei TAKEHARA
1993 Volume 13 Issue Supplement2 Pages
131-134
Published: October 01, 1993
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In flow visualization, difference of refractive indices of air, water and glass causes troubles. Some of them can be solved by making the refractive indices of glass and water, while it is impossible to match them between air and water.
Relatively low refractive index is expected in some kinds of fluoride glasses. An attempt is made to produce glass particles of a three-phase glass of MgF
2, CaF
2 and AlF
3, of which refractive index is slightly larger than that of water, i.e., 1.333. As dissolution of KI increases the refractive index of the solution, the produced particles virtually disappear in the water with addition of some KI. For the condition, the refractive index of water, which is the same as the particles, is measured by a refractometer and estimated to be 1.398.
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Hidenobu YANO, Mitsuharu MASUDA, Yukimasa KAWANO, Yoshitomo SATO, Kazu ...
1993 Volume 13 Issue Supplement2 Pages
135-138
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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In the gas atomization method, the molten metal is atomized by supersonic freejets. However, the breakup process of the melted metal droplet is not known. In the present research, the diagnostic system based on the inline laser-holography is constructed to clarify the process of gas atomization. This method determines the size and location of a droplet by comparing the hologram pattern obtained by experiments with that by the theory. Previous works used the first and the second extrema of the hologram pattern for the particle sizing. However, it is found that the accuracy can be improved by considering the third extremum.
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Manabu MAESHIMA
1993 Volume 13 Issue Supplement2 Pages
139-142
Published: October 01, 1993
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At the nodes of standing wave particles in the medium alternatively receive contractive and expansive forces, and this causes the build up of the heat. 24KHz of ultrasound is continuously introduced into the one end of the acrylic bar, which is laid horizontally and 1.5 cm wide and 0.5 cm thick. The other end works just as the free end. The standing wave is well established when the length of the bar is 13.5, 18.5, 23.0 and 27.5 cm in every 4.5-5.0 cm. The thermographic pictures of these bars showed distinctive hot and cold images. Hot parts are nodes where the stress is high and the distance between each node is 4.7 cm which is nearly as same as a half-wavelength theoretically estimated. Then fine sand particles (about 10μm) distributed uniformly on the acrylic bar also draw a patterned image. The bands of sand gathèred locate almost same spots of the hot parts, which are the nodes. This phenomenon is very interesting and further discussion is necessary to describe why the sandy particles tend to gather at the nodes.
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Masahiro INOUE, Mitsuharu MASUDA, Masato FURUKAWA, Takashi MURAISHI, Y ...
1993 Volume 13 Issue Supplement2 Pages
143-146
Published: October 01, 1993
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In the large-scale gas or steam turbine, the flow around the blade tip becomes transonic, and the shock waves are generated in the blade passage. These shock waves induce the boundary layer separation and the vibrations of blades. This unstable flow phenomenon is closely related to the secondary flow associated with the large change in flow direction in the blade passage. To simulate the flow in the blade passage, the rectangular duct with swept-back bump was made. The laser-induced fluorescence (LIF) method previously developed was applied to measure the temperature distribution in the duct, and the complicated pattern of the three-dimensional transonic flow field was clarified.
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Toshiyuki KAMEOKA
1993 Volume 13 Issue Supplement2 Pages
147-152
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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Natural convective heat transfer on several arries of IC package type resistance elements is made clear by the experiments in silicone oil. The heat transfer characteristics are shown by the relation between Nu and Ra. Flow and temperature fields around the resistance elements are visualized by using two kinds of liquid crystal with difference temperature ranges. The velocity of fluid around the elements is measured with the path lines of liquid crystal particles. The temperature of fluid and that of element surface are measured by the thermocouples. The relation between heat transfer and flow field is examined with the visualized color pictures.
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Shinji KUBO, Norio AKINO, Mitsunobu AKIYAMA, Hitoshi SUGIYAMA
1993 Volume 13 Issue Supplement2 Pages
153-156
Published: October 01, 1993
Released on J-STAGE: July 31, 2009
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The relationships between the temperature and the color changes of ther-mochromic materials were investigated using a spectrometer and TV camera. Samples in sheet form have reversible reaction about color changes. From spec-tra, it was found that strong absorbent bands were related to sample colors which were red, green and blue. Intensities of these absorption were varied by temperature changes. Samples showed same characteristics about correlations between brightness and the temperature, especially histeresis. It was clarified temperature profile can be measured by these thermochromic materials.
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