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Kazuhiro MURAI, Yousuke KAWASHIMA, Shigeyasu NAKANISHI
1991 Volume 11 Issue Supplement2 Pages
213-216
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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In the present paper, a finite difference numerical procedure of the standard version of k-ε turbulent model has been conducted to predict the turbulent flow in a two-dimensional square cavity for Reynolds No.=10
4-4×10
4. The formulation of wall function is simplified to evaluate the variables adjacent to wall in the present calculation. Furthermore, the calculation of the cavity flow with resistance has been performed. In comparison with several flow patterns of visualization by using a laser sheet, a reasonable agreement has been obtained.
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Shigeru ASO, Keiichi KARASHIMA, Kiyoshi SATO, Satoshi OKUYAMA, Syozo M ...
1991 Volume 11 Issue Supplement2 Pages
217-220
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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Secondary separation phenomena in three-dimensional shock wave/turbulent boundary layer interaction regions induced by sharp fin and blunt fin have been investigated. A color oil source method, in which various color oil are oozed through many holes on the interaction surface, are applied for details visualization of separated region as well as conventional oil flow technique.
For sharp fin separated region increases as attach angle is increased. Also at higher attack angle a separated region is divided into two parts. The outer part is located next to the primary separation line and oil flow lines are almost parallel to the primary separation line. The inner part is located between the outer part and fin and 'S' type oil flow lines are quite significant.
For blunt fin separated region at freestream Mach number of 2, 3 and 4 are visualized. The results show separated flow patterns changes between Mach number 3, and 4. Also at Mach number of 4, secondary separation region become quite obvious by using the color oil source method.
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Matunosuke Iwasaki, Kensuke Matuo, Shuuji Honda
1991 Volume 11 Issue Supplement2 Pages
221-226
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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The vortex shedding and near wake flows of blunt trailing edge NACA 0012 airfoils and flat plates having rectangular trailing edge cavities are observed in Mach 0.6 Shock tube flow with a Schlieren system.
While the sharp trailing edge generates only one discrete vortex, strong many discrete vortices are generated from blunt trairing edges. On the other hand dull and weak vortices can be seemed for the segmented blunt trailing edge.Circular cylindrical waves are formed due to the generation of discrete vortices.
For blunt trailing edge airfoils with angle of attack vortices are shedded from the portion near the lower corner of the trailing edge, and their mean rear stagnation points seem to be near here.It can be thought that this is a reason why blunt trailing edge airfoils have higher lift.
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Tosiyuki AOKI, Akihiro NAKAMURA, Mituharu MASUDA, Kazuyasu MATSUO
1991 Volume 11 Issue Supplement2 Pages
227-230
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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The purpose of this paper is to report gas dynamic characteristics in supersonic MHD generator, especially such as shock-boundary layer interaction occurring in the channel. The plasma for an MHD generator is produced using a shock tunnel. In order to have a clear and sharp image of the shock-boundary layer interaction in an MHD channel, the color Schlieren photographic method has been employed. The experimental results show the interaction in generator channel. The output current density decreases when the shock wave passes. The interaction in generator channel has been discussed in detail.
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Heuy Dong KIM, Hiromu KONDOH, Shigetoshi KAWAGOE, Kazuyasu MATSUO
1991 Volume 11 Issue Supplement2 Pages
231-234
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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Shock oscillations caused by shock wave / boundary layer interaction in a supersonic nozzle were measured using pressure transducers, schlieren photographs, and Line Image Sensor collimated with schlieren light source. Simultaneous measurements of fluctuating wall pressures and shock images were made to analyze the shock oscillation phenomenon. The shock images oscillating could be successfully captured by Line Image Sensor. The present report aims at adding a knowledge to the previous experiences on shock oscillations, and thereby at better understanding of its mechanism. The present measurements show that the streamwise extent of shock excursion are significantly different from the results of the previous works conducted by the pressure signals alone.
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Mitsuharu MASUDA, Hidenobu YANO, Hiromitsu KIYOSE, Yoshitomo SATO, Kaz ...
1991 Volume 11 Issue Supplement2 Pages
235-238
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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Gas atomization has become one of the most efficient means of producing metal powders. In this method, the molten metal is atomized by supersonic freejets, and the powder with the diameter less than 30 μm is now being obtained. However, the detailed structure of the jet as well as the breakup process of the melted metal droplet is not known. In the present research, the diagnostic system based on the laser holography is constructed to clarify the process of gas atomization, and the breakup process of water droplet by supersonic jet is obtained.
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High-Speed Streak Holographic Recording System
Keishi Nishihara, Kunihito Nagayama, Terutoshi Murakami
1991 Volume 11 Issue Supplement2 Pages
239-242
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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New method has been proposed of recording holographic information continuously with time. This new type of holography has been named as "streak holography." By the analysis of the record, it is possible to obtain the trajectory of the object in 3-dimensional space. A streak camera system has been constructed for this purpose. A ring-shaped film mounted on a thin duralmin disk has been driven to rotate by an air turbine spindle. Feasibility of the system has been examined by a simple experiment like free fall of small glass particles illuminated by an Ar laser.
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Sachiko Hatano, Kunihito Nagayama, Terutoshi Murakami
1991 Volume 11 Issue Supplement2 Pages
243-246
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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A new laser holographic technique has been developed to visualize sub-micron particles. If the size of the particle is comparable with or less than wavelength, it is very difficult to obtain the image of small particles by the conventional optical method.
We have obtained the holographic interference fringes by means of superposition of the reference light and the scattered light of comparable intensity by a particle irradiated at the beam waist of focused coherent light. The two-dimensional particle location is measured in terms of the center of holographic fringes, and the three dimensional depth of particle position from the recording plane is obtained by the reconstruction of the hologram.
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Hitoshi NISHIYAMA, Atsushi OKAJIMA
1991 Volume 11 Issue Supplement2 Pages
247-250
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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This paper presents the correction method for image distorted through cylindrical surface. This method contains geometrical shape factor, refractive indexes on both inner and outer sides of a cylindrical vessel. We employed the law of reflaction and geometrical relations to obtain the equation. This method was applied to two examples and was verified.
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Fundamental Properties of Photochromic Dyes of Spiropirans
Tomohide NI-IMI, Shintaro YAMASHITA, Tetsuo FUJIMOTO, Yasuhiro TAKENAK ...
1991 Volume 11 Issue Supplement2 Pages
251-254
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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In this research, fundamental experiments for application of photochromism to fluid measurements and flow visualization are carried out. For use of photochromism in fluid measurements and flow visualization, it is necessary that the most suitable density of dye and power of the laser are selected. The excimer laser beam (wave length=308 nm) is used to form a dye trace. The dye is dissolved in ethanol. Length and thickness of the dye trace, depending on the concentration of dye (0.04-0.00075 weight %), are measured by a CCD camera. It is found that the length of the dye trace is longer for low concentration of dye than for high concentration. The approximated distributions of thickness of the dye trace enables to predict the length of the trace depending on the concentration of dye.
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Takasi USUI, Tomomasa UEMURA, Fujio YAMAMOTO, Manabu IGUCHI
1991 Volume 11 Issue Supplement2 Pages
255-258
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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In the 3D-PTV, 3D coordinates of tracers are determined by the stereo range finding method. Recently authors developed a new efficient method of determining 3D locations of tracer particles from two to three 2D pictures. The method based on the optimum arrangement of cameras and an algorithm which is capable of reducing an amount of calculations in the process of the stereo range finder. The present method has shown such a high performance that can finish all the process in a very short time, for example 25ms to determine a location of one particle utilizing an ordinary 16bit-personal-computer.
Takasi USUI*, Tomomasa UEMURA*, Fujio YAMAMOTO, Manabu IGUCHI
Efficient Method to Find Stereo-Match Pairs from Pictures of Distributed particles
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Fujio YAMAMOTO, Tomomasa UEMURA, Manabu IGUCHI, Zen-ichiro MORITA
1991 Volume 11 Issue Supplement2 Pages
259-262
Published: October 01, 1991
Released on J-STAGE: December 08, 2009
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A binary correlation method with a high speed algorithm for the particle tracking velocimetry (PTV) is applied to the measurement of mixing gas-liquid two phase flows in a cylindricall bath with a bottom blowing bubbling jet. By analyzing a series of pictures of moving particles and bubbles in the water bath, flow patterns, instantaneous velocity distribution, time mean velocity distribution, velocity fluctuation and rising velocity of bubbles are obtained. It is made clear that the mixing flow is agitated by the bubbling jet and that the fluctuation of the mixing flow is governed by the rising bubbles and the unsteady vortex in the upper part of the bath.
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1st Report:Temperature measurements using micro capsuled thermo-sensing liquid crystals
Toshio Kobayashi, Tetsuo Saga, Shigeki Segawa, Toshihiko Tanaka
1991 Volume 11 Issue Supplement2 Pages
263-266
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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The Visualization technique using micro capsuled thermo-sensing liquid crystals (TLC) suspension method can be obtained to the information both temperature and velocity, simultaneously. It is, however, not so easy to apply its technique to the quantitative measurement. This paper presents a procedure to determine the instantaneous isothermal temperature distributions in a time-varying thermal flow field visualized by the TLC tracer particles. Liquid crystal video images photographed by a 3-CCD camera are digitized into three frames concerning the intensities of red, green and blue light. These three RGB images are filtrated by the weighted averaging method. By using Munsell color system. the relations between colors and temperatures are calibrated. This color image processing technique has been applied to the unsteady thermal flow field, and two dimensional isothermal temperature distributions were successfully measured.
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An introduction of a conditional sampling to PIV
Deog Hee DOH, Toshio KOBAYASHI, Tetsuo SAGA, Hisayuki KANAMORI, Hisako ...
1991 Volume 11 Issue Supplement2 Pages
267-272
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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A conditional sampling technique has been introduced to the Particle-Imaging Velocimetry. The image processing system desingned specifically for conditional image sampling which consists of a laser light sheet, a TV camera and a image processor with a time difference detector allows to extract the images of the settled conditions from consecutive TV frame images. To confirm the ability and utility of this technique, the system has been applied to the flows behind a rotating propeller, and the time-averaged velocity distribu-tions at the four discreat rotating angles of the propeller are measured. The difference of wake structures at the each angle was clearly extracted.
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Masaaki KAWAHASHI, Kenji HOSOI, Ken-ichi TAMURA, Katuichi YAMAMOTO
1991 Volume 11 Issue Supplement2 Pages
273-276
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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Recently, factors required for design automobile air conditioning system are amenity, noise control, automatic temperature control and so on. To improve these factors, basic analysis of flows in a heater unit or in ducts of air conditioning system is very important.
In this report, velocity measurements and visualization of flows in a practical model of heater unit are carried out by means of the dual-beam-sweep laser speckle velocimetry, and flow patterns obtained by different operation modes are investigated.
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Shinzaburo UMEDA, Wen-Jei YANG
1991 Volume 11 Issue Supplement2 Pages
277-280
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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In this paper, the motion of surface-floating particles in the various fluid flows in a curved channel is numerically studied. The purpose of this study is to investigate the role of the dimensionless parameter t ?? /Cd in particle tracing.
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Hiroshi HAYAMI, Isao MORI, Toru KOSO, Nobumasa KAWAGUCHI
1991 Volume 11 Issue Supplement2 Pages
281-284
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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The mixing process in a cell mixer by a piezoelectric vibrating actuator as a stirrer was visualized by means of a dye-tracer method and was pictured using a video camera. The local concentration of dye was transformed to a gray scale using an image processing technique. The quantitative information on 2D mixing process as well as the flow pattern were deduced and discussed by the image processing. The time variation in the probability density function of gray scale for the whole area as well as the time variation in the local gray scale were also discussed.
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Yoshiaki CHIBA, Tomoaki INOUE, Kuniyoshi TSUBOUCHI
1991 Volume 11 Issue Supplement2 Pages
285-288
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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This paper presents the results of performance of a noncontact seal for turbopumps. Experiments of flow visualization were performed using chemical reaction methods. Test results demonstrated that leakage flows through a non-contact seal were evaluated qualitatively by observing changes in color of a indicating dye, and quantitatively by measuring the pH of the sealing water. Therefore, it has been confirmed that this evaluation method is suitable for seal performance testing.
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Kyoji KAMEMOTO, Yosifumi YOKOI, Satosi SAITO, Eiji TANAKA, Yutaka OGAW ...
1991 Volume 11 Issue Supplement2 Pages
289-294
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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In order to understand the complex flow in a vortex flow meter, water flows around a circular cylinder and a trapezoid cylinder in a circular pipe were observed with the aid of a putting-dye method, in the Reynolds number range from 780 to 19, 000 of the pipe flow. From this visualization experiments, three dimensional characteristics of the flow such as formation and shedding of 3-D vortices, formation of horse-shoe vortices and appearance of 3-D separation regions on the pipe wall, were known.
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Tomomasa UEMURA, Fujio YAMAMOTO, Manabu IGUCHI, Takeshi HORIOKA
1991 Volume 11 Issue Supplement2 Pages
295-298
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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The technique of the quantitative flow visualization is applied to measure the behaviors of bubbles in a cylindrical bath which is agitated by a bottom blown bubbling jet. Rising velocities of bubbles, distributions of bubbles, flow directions around a bubble and distributions of gas-holdups etc. are measured. Without the technique, measurements of those quantities would be rather difficult, or some are impossible.
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Toshiaki SETOGUCHI, Hideaki MAEDA, Etsuo MATSUKI, Kenji KANEKO
1991 Volume 11 Issue Supplement2 Pages
299-302
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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Experimental investigations directed towards delaying stall onset of the wells self-rectifying air turbine are reported. Three boundarylayer controls have been tested in the two-dimensional cascade tunnel. These include (1) leading edge rotating cylinder, (2) leading edge slat and (3) breather slot. The flow visualization of wake behavior by paraffin mist method has suggested that the stall angle of Wells turbine may be increased by installing leading edge slats for the blades.
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Kenji KANEKO, Toshiaki SETOGUCHI, Yoshiyuki OKAMURA
1991 Volume 11 Issue Supplement2 Pages
303-306
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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The solid casing of an ordinary diagonal-flow fan is replaced by an. annular wing with Gdttingen 625 airfoil section in order to stabilize the unstable p-Q characteristics in low flow coefficient region. The control action with the inlet annular wing is perfect and it is possible to eliminate the unstable characteristics. In this paper, the mechanism of the passive control is investigated by means of a flow visualization with tuft from the viewpoint of-three dimensional flow fields over the rotor tip region.
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Kazuhiro TANAKA, Hiroshi TSUKAMOTO, Sigenori MATSUNAGA, Hiroki TANAKA
1991 Volume 11 Issue Supplement2 Pages
307-310
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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The flow around a two-dimensional isolated airfoil is visualized in a smoke wind tunnel. The test airfoil consists of the leading and trailing parts, which is fixed on the test section wall. The leading one can be rotated not more than 9 degrees around the point of 1/4 chord length. The flow visualization was carried out under the following conditions; Reynolds Number Re=1.01×104-2.82×10 5, attack angle α=0-20 degrees. The visualized result shows that the shape changing can control the flow field around the airfoil near the stall angle of the original shape.
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Shigeru ASO, Noriyuki KANEHIRA, Atsuhiro SAKAMOTO
1991 Volume 11 Issue Supplement2 Pages
311-314
Published: October 01, 1991
Released on J-STAGE: July 31, 2009
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Dynamic stall phenomena have been investigated numerically by solving incompressible Navier-Stokes equations by a third-order upwind scheme in order to reveal the flow structure and mechanism of dynamic stall. Separated flows around oscillating airfoil in pitch are calculated by using moving mesh system. The calculated separated region is small in pitchingup process and it becomes large in a pitching-down process. Quite different characteristics of flow patterns between in a pitching-up and pitching-down processes are obtained. Hysteresis curves of CL and CM are simulated.
Also the separated flow fields around pitching airfoil are visualized experimentally. The results show the flow patterns and extent of separated region in pitching-up and pitching-down processes are quite different and significant characteristics of dynamic stall is obtained.
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