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Volume 19, Issue 74
Displaying 1-10 of 10 articles from this issue
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Needs of Accurate Prediction and Effective Dissemination of InformationYoshi SASAKI1999 Volume 19 Issue 74 Pages 187-192_1
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
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Yuji WADA1999 Volume 19 Issue 74 Pages 193-195_1
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
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Teruo HARASHIMA1999 Volume 19 Issue 74 Pages 196-200_1
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
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Akihiro OGAWA, Yuko OSHIMA1999 Volume 19 Issue 74 Pages 201-206_1
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
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Toshikazu NAKAJIMA1999 Volume 19 Issue 74 Pages 207-208
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
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(Visualizations of Flow and Cooling Process)Masahiro NAKASHIMA, Tsutomu NOZAKI, Takahide TABATA1999 Volume 19 Issue 74 Pages 209-214
Published: July 01, 1999
Released on J-STAGE: December 08, 2009
JOURNAL FREE ACCESSThis paper is concerned with the cooling unit, where the flow mechanism of fluidics called the vortex chamber oscillation device is applied. The water jet issuing from this cooling device impinges on the heated plate with swinging by itself. The flow aspect in the cooling device and the impinging patterns of the water jet have been studied by means of the high speed digital video camera and the image processing system. As a result, the oscillating period is estimated by the sequential frames from this camera. The large scale vortex is recognized in the vector diagram obtained by the PIV system. The discussions about the oscillating mechanism has been conducted by using this large vortex. Moreover, the cooling process is also visualized by using the temperature-sensitive liquid crystal film. The effects and the merits of this cooling device have been discussed.View full abstractDownload PDF (5729K) -
Hiroki MATSUMOTO, Kohshi NISHIDA, Ken-ichi SAITOH1999 Volume 19 Issue 74 Pages 215-222
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
JOURNAL FREE ACCESSThis paper deals with noise reduction effect of partition disks on aerodynamic noise generated by curved columns in uniform air flow. The curved column is formed in Vshape by bending a straight column to an angle of 2θ. The bend part has a radius of curvature of R. Aerodynamic sounds generated by the curved columns are affected by the values of θ. When θ ?? 90°, eminent aeolian tones are generated by the curved columns. But when θ>90°, the aeolian tones are not generated, the broad band noises are generated by the curved columns. In this paper in order to decrease aeolian tones, two partition disks are attached to a bend part, and its noise reduction effect is investigated experimentally. The result shows that it becomes clear that the disks are very effective to reduce the aeolian tone. The flow visualization around the curved column with partition disks by the tuft stick method, the oil dots method and the oil film method becomes clear the mechanism of noise reduction.View full abstractDownload PDF (8563K) -
Mitsuo WATANABE, Satoshi HASEGAWA, Tomoyuki HASHIMOTO, Hitoshi YAMADA1999 Volume 19 Issue 74 Pages 223-229
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
JOURNAL FREE ACCESSDuring the development of a liquid oxygen turbopump for the LE-7 engine of the H-II rocket, super-synchronous shaft vibrations (1.0-1.3ω) in the inducer were often observed. From the research of the vibration performance of the inducer, it was concluded that such vibrations were caused by the rotating cavitation in the inducer and it was also shown that the moderately increased diameter of the pump inlet was most effective to suppress such vibrations. To investigate those unstable phenomena in the inducer in detail, suction performance test of the inducer using a cavitation tunnel were conducted. From the results of the high-speed photograph analyzer and of the spectrum analysis of the shaft vibration, three types of unstable cavitation modes, rotating cavitation, steady asymmetric cavitation and low cycle oscillation were observed. In this paper, the visual observation and its analysis results of unstable cavitation oscillation were reported in detail.View full abstractDownload PDF (4783K) -
The Case Where Impinging Wall is Placed in Potential Core Region of Free JetMinoru FUKUHARA, Hirokazu SONODA, Tsutomu NOZAKI, Hiroki NOGUCHI, Hide ...1999 Volume 19 Issue 74 Pages 230-236
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
JOURNAL FREE ACCESSCooling characteristics of the heating wall by the circular free jet added the annular suction flow, was examined. This experiment was carried out the case where the impinging wall is placed in the potential core region of the circular free jet. As a result, it was found that the higher Nusselt number is obtained in the case where the suction flow is added than in the case where the suction flow is not added independent of the distance between the exit of the pipe and the wall. Furthermore it was found that as the distance increases, the ratio of the suction velocity to the jet velocity showing the maximum Nusselt number becomes small. It was clarified by using PIV that these heat transfer characteristics are closely related with the fluctuating velocity and the time mean velocity.View full abstractDownload PDF (552K) -
Katashi KUROKAWA, Terumi INAGAKI, Masahiro AGU, Yoshizo OKAMOTO1999 Volume 19 Issue 74 Pages 237-242
Published: July 01, 1999
Released on J-STAGE: July 31, 2009
JOURNAL FREE ACCESSThe minimum detectable size, as a resolution, is one of the most important performance indices of thermograph. This index represents the ability as to how small size can be detected on the display screen, and smaller value indicates more precise measurement of an object to be measured. In case that temperature measurement is a purpose, identification of the minimum detectable size alone is insufficient. It is necessary to clarify the relationship between the size of an object to be measured and the temperature reading.
This study pays attention to its point, and has quantitatively discussed the aberration of lens, the frequency response of signal processing amplifier and the defocus, respectively, as the major factors that deteriorate the performance indices of typical mechanical scanning thermograph. Then, the theoretical minimum detectable size and the temperature reading of the system have been comparatively studied, and the relation of them has been clarified with actual measuring values.View full abstractDownload PDF (510K)
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