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Tetsuo NISHIYAMA, Kenichi FUNAZAKI
1986 Volume 52 Issue 475 Pages
1005-1013
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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Yoshifumi OHGAMI, Teruaki AKAMATSU
1986 Volume 52 Issue 475 Pages
1014-1023
Published: March 25, 1986
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Takayoshi MUTO, Hirotaka KAYUKAWA
1986 Volume 52 Issue 475 Pages
1024-1031
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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Masataka SHIRAKASHI, Hiroyuki KAWASE, Shoichi WAKIYA
1986 Volume 52 Issue 475 Pages
1032-1039
Published: March 25, 1986
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Kenichi YAMASHITA, Kikaku IKEMORI
1986 Volume 52 Issue 475 Pages
1040-1049
Published: March 25, 1986
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Masahiro YAMABE, Shoji ITO
1986 Volume 52 Issue 475 Pages
1050-1059
Published: March 25, 1986
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Yasutoshi SENOO, Masahiro ISHIDA
1986 Volume 52 Issue 475 Pages
1060-1069
Published: March 25, 1986
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Akio SAITO, Yoshio UTAKA, Seiji OKAWA, Kozo KATAYAMA
1986 Volume 52 Issue 475 Pages
1070-1077
Published: March 25, 1986
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Masataka SATO
1986 Volume 52 Issue 475 Pages
1078-1085
Published: March 25, 1986
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Michio YANADORI, Kunio HIJIKATA, Yasuo MORI, Motokazu UCHIDA
1986 Volume 52 Issue 475 Pages
1086-1094
Published: March 25, 1986
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Nobunori OSHIMA
1986 Volume 52 Issue 475 Pages
1095-1101
Published: March 25, 1986
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Nobunori OSHIMA
1986 Volume 52 Issue 475 Pages
1102-1109
Published: March 25, 1986
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Tatsuyuki OKAMOTO, Toshimi TAKAGI, Satoshi FUJIWARA, Toshihiko TAKEMUR ...
1986 Volume 52 Issue 475 Pages
1110-1117
Published: March 25, 1986
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Yoshio YONEZAWA, Norimasa IIDA, Osamu KAWAGUCHI, Takeshi SATO
1986 Volume 52 Issue 475 Pages
1118-1126
Published: March 25, 1986
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Norimasa IIDA, Yoshio YONEZAWA, Osamu KAWAGUCHI, Takeshi SATO
1986 Volume 52 Issue 475 Pages
1127-1135
Published: March 25, 1986
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Katsunori HANAMURA, Ryozo ECHIGO, Yoshio YOSHIZAWA, Toshio TOMIMURA, M ...
1986 Volume 52 Issue 475 Pages
1136-1143
Published: March 25, 1986
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Yoshiaki ONUMA, Norihiko YOSHIKAWA, Masahiko UMETANI, Kazuhiro KIMURA
1986 Volume 52 Issue 475 Pages
1144-1150
Published: March 25, 1986
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?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??, ?? ?? ?? ?? ?? ?? ?? ?? ??, ?? ??, ?? ??, ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? . ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??, ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??, ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??, ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? .
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Yoshiaki ONUMA, Norihiko YOSHIKAWA, Masahiko UMETANI, Kaszuhiro KIMURA
1986 Volume 52 Issue 475 Pages
1151-1157
Published: March 25, 1986
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Masateru SHIMOTSU, Takashi OBARA, Toshiyasu SHIMONAKA, Toshiaki SUMA
1986 Volume 52 Issue 475 Pages
1158-1167
Published: March 25, 1986
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Yoichiro MATSUMOTO
1986 Volume 52 Issue 475 Pages
1168-1174
Published: March 25, 1986
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Noncondensable gas inside a cavitation bubble has much influence on the collapse of the bubble and also on the growth. When the bubble is shrinking, the noncondensable gas accumulates near the bubble wall and the vapor has to diffuse the gas layer to condense. When the bubble is growing, the evaporated vapor stays near the bubble wall. In both cases, the difference between the saturated vapor pressure and the vapor pressure on the wall becomes smaller. Therefore, the diffusion process prevents the condensation and the evaporation of the vapor on the bubble wall accompanied with a bubble motion. This effect is important in the collapsing period, especially in the rebounding period. At this moment, the rate of condensation becomes less than 0.1 percent compared with the case where the diffusion coefficient is assumed to be infinite.
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Hiroshi SAKAMOTO, Hiroyuki HANIU, Yoshihiro OBATA
1986 Volume 52 Issue 475 Pages
1175-1183
Published: March 25, 1986
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Time-mean and fluctuating forces acting on two rectangular prisms of the same dimension in tandem arrangement placed in a uniform flow were investigated experimentally. The results were summarized in several figures from which one can obtain the time-mean drag, the fluctuating drag, the fluctuating lift and the Strouhal number for the various distance between the two prisms. Further, the behavior of the fluctuating lift and drag obtained from the conditional sampling based on the velocity signal of the periodic vortex shedding were presented and discussed. The vortex shedding from the downstream prism was trigered by the arrival of the vortices from the upstream prism when the distance between the two prisms exceeds three times of the prism width. Phase shift between the fluctuating lift generated by the vortex shedding was founded to be proportional to the distance between the two prisms.
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Nobuyuki SATOFUKA, Hidetoshi NISHIDA, Teiichi TAMAKI, Atsushi SHIMIZU
1986 Volume 52 Issue 475 Pages
1184-1190
Published: March 25, 1986
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An approximate factorization scheme has been developed for analyzing transonic cascade flows. In this scheme, upwind differencing is used for introducing artificial viscosity in the supersonic region, and central differencing in the subsonic region. The resulting simple two- and three-banded matrices are solved by the relaxation procedure. In this paper, the efficiency of this scheme is demonstrated by solving the channel flow problem, and then this scheme is applied to some transonic cascade flows. The results are in good agreement with those obtained by other methods.
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Tyozi HORIKOSI, Tosihiko IKEDA, Itiro ASANO
1986 Volume 52 Issue 475 Pages
1191-1196
Published: March 25, 1986
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The relationship between the oscillations of the rectangular jet and the vortex behaviour formed in the shear layer has been investigated experimentally. The flow patterns could be found to change with the Reynolds number and the splitter distance, and they are divided into three kinds : In flow pattern 1, the jet oscillations do not occur and the vortex is not formed. In flow pattern 2, the Strouhal number of the jet oscillations is equal to that of the vortex is not formed. In flow pattern 3, the Strouhal number of the vortex formation is larger than that of the jet oscillations. In addition, the structure of the jet oscillations has been investigated by means of measuring the velocity fluctuations and the frequency spectra, as well as the flow visualization.
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Takahiko TANAHASHI, Tatsuo SAWADA, Eriya KANAI, Akira CHINO, Tsuneyo A ...
1986 Volume 52 Issue 475 Pages
1197-1206
Published: March 25, 1986
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The flow normal to an infinite thin elliptic cylinder which is uniformly accelerated from rest in a direction perpendicular to its generating lines in a viscous fluid is considered. The Dufort-Frankel method for the vorticity transport equation is used for the numerical simulation of viscous incompressible flows, and a new finite Fourier transform method is introduced in order to handle the stream function equation for accurate and efficient calculation. A major part of the present paper is devoted to physical properties of the flow for the early stages of development of the wake behind the obstacle for Reynolds number 98. 11. A computer-aided flow visualization method is used to demonstrate the main features of the hydrodynamic field for the flow. The rest of this paper demonstrates the important unsteady forces such as time-dependent drag, lift and moment acting on the body immersed in a viscous fluid, and presents specific numerical results for various transition.
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Takatsune NARUMI, Tomiichi HASEGAWA
1986 Volume 52 Issue 475 Pages
1207-1214
Published: March 25, 1986
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An experimental study has been made on the flow of viscoelastic inquids in thin films held between a flat plate and a spherical surface of a large radius of curvature, Especially, the case is investigated when a spherical surface begins to roll on a flat plate from a stationary and contacting state. Dilute polymer solutions are used as viscoelastic fluids, whose properties are elastic but Newtonian in viscosity. compared with non-elastic liquid, some effects are shown : The point of cavitation is far from the center of contact where the thickness of the liquid film is minimum. The thickness of the liquid film, generated with a rolling movement, is larger than that of non-elastic liquids.
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Yukio TOMITA, Yukio ISHIBASHI, Toshio YOKOYAMA
1986 Volume 52 Issue 475 Pages
1215-1221
Published: March 25, 1986
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In this paper, electrostatic drop formation characteristics in the use of water-based ink are reported, for applications to ink jet devices. In order to make clear experimentally the electrostatic uniform drop formation phenomenon, applied voltage, flow rate, nozzle diameter and distance between the nozzle tip and the electrode are widely varied. In addition, liquids having different values of electric conductivity, surface tension and viscosity are used, and the experiments are carried out to examine the effects of these factors on the uniform drop formation. Then, the relations among the various factors governing the uniform drop formation phenomenon are found by using dimensional analysis.
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Terushige FUJII, Koji AKAGAWA
1986 Volume 52 Issue 475 Pages
1222-1227
Published: March 25, 1986
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Water hammer phenomena caused by a sudden valve closure investigated in one-component two-phase flows. The phenomena in one-component two-phase flows are more complicated than those in two-component two-phase flows because of the presence of mass transfer between liquid and vapor. Basic partial differential equations based on a one-dimensional homogeneous flow model are solved analytically by linearization and iterated Laplace transformation. The profiles of the pressure transients at the closing valve are given. It is shown that the mass transfer between the two phases has a great influence on the profile of the pressure transients, and that the magnitude of the influence depends on the relaxation time τ
M of the interphase mass transfer.
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Toshihiro TAKAMI, Kouzou SUDOU, Yukio TOMITA
1986 Volume 52 Issue 475 Pages
1228-1234
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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A steady fully-developed laminar flow of power-law fluids in curved pipes has been solved numerically for Dean numbers D<1000, power indices 0.5<n<1.0 and curvature radius ratios 10<Rc<100. Velocity profiles of primary flow, stream lines of secondary flow, distributions of wall shear stress and friction factors are obtained. Effects of D, n and Rc upon flow characteristics made clear.
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Toshihiro TAKAMI, Kouzou SUDOU, Yukio TOMITA
1986 Volume 52 Issue 475 Pages
1235-1242
Published: March 25, 1986
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A steady fully-developed laminar flow of power-law fluids in curved pipes has been analyzed using boundary layer approximations in order to obtain the friction factor for high Dean numbers. Experimental results for the friction factor are compared with the analytical results. Also, a flow in curved pipes of elliptic cross section has been investigated experimentally.
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Hisataka TAMURA, Masaru KIYA, Toshiya NOZAWA
1986 Volume 52 Issue 475 Pages
1243-1248
Published: March 25, 1986
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Fluctuating pressure on the surface of a circular cylinder in and near a plane turbulent mixing layer was measured as having a Reynolds number of 4.6×10
4, based on the cylinder diameter d and the main-flow velocity ; the diameter being approximately 2 thicknesses δ of the mixing layer. the r.m.s. value and the autocorrelation of fluctuating lift and drag were computed from the r.m.s. value and the circumferential cross-correlation of the surface-pressure fluctuation. The r.m.s. value and the circumferential cross-correlation of the surface-pressure fluctuation. The r.m.s. lift was found to attain a large maximum when the center of the cylinder was located near the high-speed edge of the mixing layer ; the maximum value was much greater than the r.m.s. lift obtained in the main flow. The present data, together with authors' previous results, enables the representation of the maximum r.m.s. lift as a function of the ratio d/δ. It appears that the maximum lift is associated with a bodily lateral oscillation of the mixing layer upstream of the cylinder. The oscillation enhances both the strength of the vortices shed from the cylinder, and the periodicity of the vortex shedding. The disturbance of the enhanced vortex shedding propagates upstream and in turn forces the oscillation of the mixing layer. This is a feed-back mechanism.
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Nobuyuki FUJISAWA, Hiroyuki SHIRAI
1986 Volume 52 Issue 475 Pages
1249-1254
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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Stability analysis for the occurrence of Taylor-Gortler vortices in turbulent wall jets along concave surfaces is studied by comparative experiment. The eddy viscosity expression in the perturbation equations are determined from a modified version of a two-equation turbulence model including curvature, which predictes well the main features of the turbulent wall jets along concave surfaces. From the stability analysis, it is found that the minimum curvature at the neutral stability state decreases slightly as the Reynolds number increases. Then, the theoretical minimum curvature reaches good agreement with the experiment, when the eddy viscosity expression is treated as a function of curvature.
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Ryuichiro YAMANE, Yutaka TANAKA, Yoshihiro MOCHIMARU, Miki YAGITA, Mas ...
1986 Volume 52 Issue 475 Pages
1255-1260
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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The authors have reported that the two-dimensional Karman vortices behind a cicular cylinder are broken into lengths of about 8d and form chains of spoon-shaped vortex couples. In the present experiment disks were attatched to the cylinder so that the Karman vortices were artificially cut at fixed positions with fixed lengths of 4d, 4d, 8d and 10d. The structures with 8d were most stable, forming the vortex chains with least irregularities, and the wake was much wider than that without the disks, while the neighbouring vortices with a length 4d were merged to the scale of about 8d. There results show that the length 8d is a unique scale in the deformation of the Karman vortices to the three-dimensional large-scale structure.
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Akihiko ITO, Masao SASAKI
1986 Volume 52 Issue 475 Pages
1261-1265
Published: March 25, 1986
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A thin water film flowing down an inclined plane was investigated with regard to the breakdown and formation of liquid film. The contact angle at the stagnation point of the dry patch was measured by laser beam refraction. The film thickness and wave properties, such as velocity, height and frequency were also measured. On the basis of the experimental results, the balance of force acting on a dry patch was examined for the two layer model, which consists of a base film and wave layers. A dry patch vanishes when the dynamic pressure force mainly due to a disturbance wave is superior to the surface tension force. It is concluded that the main factor to rewet is the spreading of a disturbance wave.
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Akihiko ITO, Masao SASAKI
1986 Volume 52 Issue 475 Pages
1266-1269
Published: March 25, 1986
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A thin water film down an inclined plane was investigated with regard to the breakdown and formation of a liquid film. In this paper, the effect of the surface roughness of a plane on liquid film formation was experimentally examined. The minimum wetting rate on a rough plane is considerably small compared with that of a smooth plane in the disturbance wave region. On the other hand, the retrograde contact angle sharply decreases with the increase of surface roughness. It is easy to maintain liquid film on a rough surface. Therefore, the minimum wetting rate on a rough surface depends not on the time average, but on the maximum dynamic pressure due to a disturbance wave.
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Yukio HOHSHO, Kimiaki KAN, Toshikazu KADOTA
1986 Volume 52 Issue 475 Pages
1270-1276
Published: March 25, 1986
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An experimental study was made to obtain fundamental information on the characteristics of the spray flow issuing from a windshield washer nozzle. The momentum flux in the spray flow in an air stream with uniform velocity distribution was measured with a balance, and photographic observation of the spray flow on a simulated windshield was also done using a He-Ne laser. For the better understanding of the measured results, theoretical analysis was made of the spray configuration based on the single droplet behavior, taking account of the momentum imparted to the air by the initial droplets. The results derived form the theoretical analysis agreed fairly well with experimental ones.
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Koji AKAGAWA, Toshihisa ISHIDA, Terusige FUJI, Hiroaki KUTSUNA, Kazuno ...
1986 Volume 52 Issue 475 Pages
1277-1284
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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An experiment on single phase natural circulation was conducted in a closed loop with a U-shaped cooler. The loop consists of an inverse U-shaped tube cooler, two parallel heating boxes and connecting bent pipes. Tests were made at atmospheric pressure by holding the heater input (Q=0.5 kW to 3.5 kW) constant, and the cooling water flow rate of the cooler constant, during various transient elevation differences between the heater and the cooler. The observed transient flows were classified as three regimes : stable, neutrally stable, and unstable type, the flow developed a reverse flow and, afterwards, it oscillated with a periodic reversal of flow. A characteristic of the flow oscillation was described with relation to the period and the length of flow path, and the oscillation mechanism was discussed for the change of buoyancies and flow. The flow oscillation was found to stem from the flow change in the inverse U-shaped flow paths of the cooler and the hotleg, including the heater.
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Hiroyuki HASHIMOTO, Rokuro SATO, Hirokuni HIYAMA
1986 Volume 52 Issue 475 Pages
1285-1290
Published: March 25, 1986
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The liquid rising effect which is investigated in this study still remains to be clarified. The objective of the present study is to obtain fundamental design data for the vibration pumping system. The experiment revealed that liquid rising could occur in a suction pipe line under the condition that the suction pipe was cut in two and the lower half was fixed so that only the upper half could be vibrated. The effect of the scale of the lower half suction pipe on the characteristics of liquid rising, was also made clear experimentally. By comparing the experimental results with the theoretical analysis, the performance of the new pumping machine could be estimated.
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Hiroshi TSUKAMOTO, Shigenori MATSUNAGA, Satoshi HATA, Keiichiro NAGANO ...
1986 Volume 52 Issue 475 Pages
1291-1299
Published: March 25, 1986
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Theoretical analysis has been developed for the prediction of transient characteristics of a centrifugal pump during its rapid acceleration/deceleration. Calculated results, by use of the presented rotating circular cascade model, agree qualitatively with the corresponding experimental ones. Both measured and calculated dynamic performances are rearranged to get a critical changing rate beyond which the assumption of quasi-steady change becomes unacceptable. As a result of this study, basic mechanism of the transient characteristics has been made clear, and then, a criterion for quasi-steady change has been presented.
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Mitsuo UNO, Shigenori MATSUNAGA, Akihiko ISHINODA, Makoto ARIMURA, Tad ...
1986 Volume 52 Issue 475 Pages
1300-1306
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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This paper presents experimental results on the wake characteristics of a mixed-flow impeller and their relation to the impeller loss. The circumferential variations of the velocity at the impeller exit were measured at various radial locations using a five-hole pressure probe with quick response. The wake profiles were examined and then the wake momentum thickness was related to total pressure losses occurring in the fluid flow across the impeller. In addition, the effect of both the centrifugal force and deceleration rate across the impeller was studied on the total pressure loss. From these results, loss and stall correlations were obtained.
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Akira OHASHI, Katsuya YANAIDA
1986 Volume 52 Issue 475 Pages
1307-1315
Published: March 25, 1986
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This paper presents the theoretical and experimental results obtained by the study of eccentric cylindrical capsule transportation. The flow in the annular section of a capsule can be approximated by the flow through double-circular pipes when the inner pipe moves. Then the general formula for the pressure loss due to friction drag in turbulent flow through double stationary pipes is derived by applying the idea of the one-seventh power law for axial velocity distribution, and the rational model for the analysis of eccentric annuli. Furthermore, by applying the results obtained in the study of concentric capsule flow, this formula is developed for the flow through double moving pipes. During the experimental part of the study, the validity of the formula is confirmed and the capsule velocity, as well as the total pressure loss which is established by friction drag and pressure drag, can be estimated with reasonable accuracy.
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Yoshio KODAMA, Tohru FUKANO
1986 Volume 52 Issue 475 Pages
1316-1324
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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The effect of the width and the location of a ring set in the clearance between a duct inner wall and a blade tip and the profile of a blade tip on fan noise are experimentally investigated by using three rings of different widths and four impellers with different tip geometry. The results are summarized as follows : A considerable amount of noise reduction can be expected by setting a ring within a tip clearance, when its initial gap is rather large. Both the noise and the aerodynamic characteristics at the maximum efficiency point are better in the case with a larger gap on the leading edge side than on the trailing edge side. In the lower flow rate range, however, the fan with a smaller tip clearance on the leading edge side is superior.
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Yutaka MIYAKE, Takehiko INABA, Tetsuaki KATO
1986 Volume 52 Issue 475 Pages
1325-1332
Published: March 25, 1986
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The authors' previous paper demonstrated that an air-separator is the most effective equipment among various different types for the improvement of unstable characteristics of an axial flow rotor. further experiments revealed that this equipment made it possible to eliminate the unstable characteristic thoroughly, if necessary, even if the blade load was unusally heavy. This paper describes the geometric condition to realize this and the discussions of the performance mechanism of the equipment on the basis of the experiments showing the discharge distribution of fluid form the blade tip to separator passage, and the pressure distribution in a blade passage at the tip section of the rotor. It is suggested that the equipment is equally useful at any stage of multi-stage rotor.
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Akira TAKIMOTO, Osamu MATSUDA, Yujiro HAYASHI
1986 Volume 52 Issue 475 Pages
1333-1341
Published: March 25, 1986
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Forced convective heat transfer with a vaporization of suspended spray droplets is investigated theoretically in taking account of the droplet transport. Numerical analyses are performed using the finite-difference method. The mechanism of spray cooling heat transfer is clarified in relation with the droplet deposition at the heated plate surface, its vaporization, and the other dynamical behavior.
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Yuujiro HAYASI, Akira TAKIMOTO, Osamu MATSUDA, Masahito ISOZAKI
1986 Volume 52 Issue 475 Pages
1342-1349
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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Heat transfer with a vaporization of suspended spray droplets is investigated under the forced convective laminar flow along a vertical heated flat plate experimentally. Two different types of liquid-droplets in their size were supplied by both means of Ultrasonic humidifier and Spray nozzles. Visual and photographic observation were carried out in addition to the measurements of temperature distribution and heat transfer rate. By comparison with the experimental and theoretical results given by preceding report, the effect of spray cooling on heat transfer are clarified.
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Takashi MASUOKA, Gen SHIMIZU
1986 Volume 52 Issue 475 Pages
1350-1354
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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The stability of natural convection in an inclined rectangular box fluid is investigated theoretically and experimentally. The Galerkin method is adopted to analyse the problem. It is found that, for small angles of inclination from the horizontal, the effects of the side walls give rise to the secondary flow in the form of stationary transverse rolls with horizontal axes parallel to the shorter side, instead of longitudinal rolls with axes oriented up the slope, predicted for the infinite fluid layer. The singular form of the stationary transverse rolls is experimentally confirmed for angles of inclination from the horizontal φ<10°15° for the aspect ratios (length of the shorter side to depth) H
y=2 and 4.
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Hiroshi HONDA, Shigeru NOZU, Yasuyuki FURUKAWA
1986 Volume 52 Issue 475 Pages
1355-1362
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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Experimental and analytical studies were made of the effect of fitting porous drainage strips to a surface, on the condensation heat transfer performance of downward-facing horizontal surfaces. A smooth surface and two finned surfaces with and without the porous drainage strips were tested for condensation of R-113 and methanol. For the finned surfaces a maked increase in the average heat transfer coefficient was obtained by use of the porous drainage strip. The maximum values of the augmentation ratios as compared to the smooth surface were 9.0 and 12.2 for R-113 and methanol, respectively. An analytical mode was developed for laminar film condensation on a finned surface with the porous drainage strip. the numerical results compared well with the measurements.
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Teruhiko YOSHIDA, Nobuki NAGAI
1986 Volume 52 Issue 475 Pages
1363-1371
Published: March 25, 1986
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The critical conditions for the breakup of a liquid droplet by air streams is investigated by using a straight type wind tunnel and an orifice type wind tunnel. It is noted that the breakup configurations of a droplet are affected by the air flow patterns, relative velocities, droplet diameters and physical properties of the liquid. The critical Weber number at which a liquid droplet begins to breakup is not constant, which differs with Hinze's results, and is given as a function of experimental conditions.
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Takeo TAKASHIMA, Yoshihiro IIDA
1986 Volume 52 Issue 475 Pages
1372-1378
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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A drop of low temperature liquids such as water, methyl alcohol, etc. is dropped onto several kinds of molten salts, molten tin and glycerine over a wide range of temperature differences. The evaporation mode of the drop is roughly classified into four types. The evaporation time curve is generally of the from of an S laid sideways, similar to the curve for a solid surface, that is, the existence of maximum and minimum evaporation time points are observed. With respect to the Leidenfrost temperature, the interface temperature at the Leidenfrost point shown to be nearly equal to the limit of superheat, independent of the critical temperature. A series of precise observation shows that the splash phenomenon does not occur on molten salts, but does occur on molten tin.
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Yasunobu FUJITA, Kunio HIRAHAYA, Shinji MATSUO, Kaneyasu NISHIKAWA
1986 Volume 52 Issue 475 Pages
1379-1386
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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Boiling characteristics of refrigerant R-113 injected into hot water flowing in a channel are revealed by analysing the vapor flow structure in a channel and by photographic observation of the flow pattern. When the flow patterns adjacent to the nozzle change from unstable, stable to column-like ones, heat transfer characteristics are improved. Flow and heat transfer characteristics in these regions, especially in the column-like region where the maximum heat transfer coefficient is attained, are made clear with regard to the effects of such parameters as the inlet temperature and the flow rate of R-113, the water inlet temperature, and the nozzle diameter.
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Fumito KAMINAGA
1986 Volume 52 Issue 475 Pages
1387-1393
Published: March 25, 1986
Released on J-STAGE: March 28, 2008
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Blowdown experiments with emphasis on an early response of depressurization were carried out on Freon-114 liquid in a horizontal tube. Visual investigations using a high-speed camera indicated that the initial flow pattern was bubbly around flashing inception points, but expansion and growth of the bubbles caused downstream liquid pushed out of the tube with a single phase. This pattern, like a slug flow, will give a higher discharge rate at an early stage of the blowdown than those calculated by current analytical models, since choking conditions will not be reached at the outlet. Measurements of local pressure and temperature showed a thermal non-equilibrium effect, which was indicated by a pressure holdup under the initial saturation pressure ; also, that the time lag of flashing inception after the passing of an initial expansion wave was less than 1ms, and the relaxation time from the non-equilibrium state was around 2 to 3 ms.
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