著者

Motomu NAKASHIMA Yohei CHIDA

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.8, no.5, pp.21-00230, 2021 (Released:2021-10-15)

参考文献数

10

被引用文献数

2

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In skateboarding as a sports event, the riders compete in difficulty and completeness of acrobatic motions called “tricks”. As a basic trick, Ollie is performed popularly. However, the basic mechanical principle of the Ollie has not been discussed to date, especially for the Ollie jump (the jumping phase of Ollie). The objective of this study was to elucidate the mechanism of Ollie jump in skateboarding. A simulation model was firstly constructed on a multibody dynamics analysis platform. Next, an experiment using an actual rider was conducted to acquire the motion of the feet during the Ollie jump. By inputting the acquired motion of the feet into the model, a simulation of Ollie jump was carried out. In addition, a parameter study with respect to the geometry of the skateboard and the motion of the rider’s feet was conducted. It was found that the simulated Ollie jump was successful since the skateboard reached a sufficient height and became sufficiently horizontal at the peak height. It was also found that the Ollie jump can be divided into five stages from the mechanical point of view. From the parameter study, it was found that large kick angle of the deck or large distance between two trucks of the deck might cause difficulty in the contact of the tail and the ground, while small kick angle or small distance between two trucks might result in excessive rotating angle of the deck. In addition, three important points for a successful Ollie jump were found to be, to produce sufficiently fast rotational movement of the skateboard around the rear wheels, to separate both feet from the deck before the tail of the deck hits the ground, and to separate the rear foot from the deck at the final stage.

著者

Luca Facciolo Pekka Nuutinen Daniel Welander

出版者

The Japan Society of Mechanical Engineers

雑誌

Proceedings of the ... International Conference on Nuclear Engineering. Book of abstracts : ICONE (ISSN:24242934)

巻号頁・発行日

pp._ICONE23-1, 2015-05-17 (Released:2017-06-19)

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The European Utility Requirements organization started the compliance assessment process of the Mitsubishi Heavy Industries EU-APWR Standard Design in 2012. The EU-APWR is an Advanced PWR, 1700 MWe class, 4-loops, 14ft active core fuel length that MHI has developed for the European market. The EU-APWR is an evolution of the Advance PWR currently under the licensing process in Japan for the Tsuruga Power Station. MHI has modified the design applying improvements in safety and economy in order to be adapted for European markets and to comply with the EUR requirements. The EU-APWR Standard Design documentation has been assessed against the EUR Volume 2 - Generic Nuclear Island requirements Revision D, issued in October 2012. The assessment is divided into 20 chapters for a total of over four thousand individual requirements. Each chapter was assigned to Assessment Performers who executed the detailed analysis of the requirements. The assessment of each requirement and the Synthesis Report have been submitted to, and scrutinized by, the Coordination Group, formed by representatives of the European Utilities together with the Vendor, and reviewed by the Administration Group and by the Steering Committee. The Synthesis Reports have been collected in the Volume 3 EU-APWR Standard Design Subset and presented to the Steering Committee, which approved the final draft in October 2014. The overall results of the assessment indicated good compliance of the EU-APWR Standard Design: 77% of the requirements resulted in compliance with EUR. This percentage increases to 85% when taking into account the requirements for which the design has been evaluated in compliance with the objectives. The requirements where the design has been judged not in compliance with EUR are less than 2%. The divergences between the EU-APWR Standard Design and the EUR concern different areas like, for instance, layout, operational capability and performance, outage operations, personal protection and radiation monitoring. Some of the incongruences result from differences in approach to the design process or from differences in the rules and standards in use in Japan and in Europe. Some analyses, like the internal hazards effects, have been performed only partially because, in Japan, such analyses are considered site-specific and are carried out at the detailed design level. The analysis of the consequences of a hydrogen explosion, and the environmental qualification methodology of equipment have not been fully developed yet. While the reactor core has been designed for an operability cycle of 24 months and can be loaded with 50% MOX fuel, no other area of the plant has been designed taking into consideration MOX fuel.

著者

Hiroshi SASAKI Naohisa TESHIROGI

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME international journal. Ser. 2, Fluids engineering, heat transfer, power, combustion, thermophysical properties (ISSN:09148817)

巻号頁・発行日

vol.33, no.3, pp.599-605, 1990-08-15 (Released:2008-02-18)

参考文献数

9

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This paper gives the experimental results obtained with a two-stroke cycle single-cylinder research engine using an electrically heated combustion chamber to simulate the combustion chamber of a low-heat-rejection(LHR) DI diesel engine with the M-combustion system. In this report, the experiment was performed to investigate the influences of combustion chamber surface temperature and swirl ratio on the combustion of a LHR DI diesel engine with the M-conbustion system. It is found that the combustion of fuel deposited on the surface is greatly affected by the combustion chamber surface temperature, and the diesel combustion is controlled by the swirl and the surface temperature of the combustion chamber.

著者

Motomu NAKASHIMA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.4, no.1, pp.94-104, 2009 (Released:2009-01-30)

参考文献数

8

被引用文献数

40 42

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The objectives of this study were to investigate the effect of trunk undulation on the swimming performance in underwater dolphin kick, and to clarify the ideal trunk undulation form. The reference swimming motion of an elite swimmer was firstly acquired from the video analysis, and input into the swimming human simulation model SWUM, which had been developed by the authors. The trunk motion was next optimized by the simulation for three objective functions: maximizing swimming speed, maximizing propulsive efficiency, and minimizing fluid force acting on hands. The following findings were obtained: In the case of maximizing swimming speed, the whole body forms a ‘C’ shape due to the in-phase trunk undulation. The swimming motion of maximizing propulsive efficiency and the reference swimming are considerably similar to each other. In both cases, the trunk moves as a seesaw with a node; whereas, the lower limbs form a traveling wave in the absolute space. The values of propulsive efficiency are around 0.2 in the cases of maximizing propulsive efficiency, minimizing fluid force on hands, and the reference swimming. The swimming motion in the case of minimizing fluid force on hands is almost the same as that of maximizing propulsive efficiency. The trunk undulation with the appropriate amplitudes and phases, especially bending at the chest, is important in realizing the swimming motion which maximizes propulsive efficiency.

著者

Mai NONOGAWA Seigo NAKAYA Masashi ISOBE Kenzen TAKEUCHI Hideyuki AZEGAMI

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

pp.21-00200, (Released:2021-09-05)

参考文献数

29

被引用文献数

1

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This study presents methods to develop a three-dimensional numerical foot model and to identify the loading condition that is used to design a stable sole for running shoes. In a previous study, the authors proposed a method to optimize the shape of the sole to increase stability while maintaining the cushioning property. In the problem formulation, the loading condition was given as a boundary force distributed on the top surface of the sole. The aim of this study is to replace the loading condition with the force and moment at the origin of the ankle joint coordinate (AJC) system by modeling a foot with a finite element model. A finite element model of a foot is constructed using X-ray CT image data, and consists of bony structures, soft tissue, and plantar fascia. The plantar fascia is set at the bottom of the bony structures. The force and moment used in the finite element analysis are identified by inverse dynamic analysis using an experimental measurement in the practical operation of the ground reaction force (GRF) when the GRF in the direction of the foot length becomes minimum. In the finite element analysis, the finite deformation containing the contact condition between the bottom surface of the foot and the ground representing a sole made of resin is considered. For an index of the shoe stability, we define a heel eversion angle (HEA) by the rotational angle of the heel with respect to an axis in the foot length direction and evaluate it by finite element analysis. The validity of the finite element foot model as well as the force and moment obtained in this study are confirmed based on the agreement in the HEA results between the experiment and finite element analysis.

著者

Kunihiko ICHIKAWA

出版者

The Japan Society of Mechanical Engineers

雑誌

Bulletin of JSME (ISSN:00213764)

巻号頁・発行日

vol.11, no.47, pp.857-865, 1968 (Released:2008-02-15)

参考文献数

2

被引用文献数

83 181

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Finding a train operation which minimizes energy consumption for leading the train from one station to the next at the specified instant and stopping it there is dealt with in this paper. Since speed limit is observed strictly in the train operation, the problem should be considered as a bounded state variable problem. It is true that solving a bounded state variable problem is universally considered extremely troublesome, but the author has recently developed a very simple and clear method. The method is applied to this problem and the optimal control law has really been obtained straightforward and definitely. The author's is again confirmed to be very convenient to solve a bounded state variable problem. The research is believed to be the first scientific research on the economization of train operation.

著者

鈴木 曠二

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.50, no.457, pp.1736-1739, 1984

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The Dynamic Soaring is the soaring technique making use of the wind gradient. The order, Albatross belongs to, includes several species which use this technique and have various scale. Main conclusion is as follows: They practice almost physically similar dynamic soaring. The larger one practices a larger dynamic soaring and requires a stronger wind than the smaller one does, in the wind near the sea surface. Such a scale effect corresponds with the fact that a Wandering Albatross lives in the zone of the westerlies of the Southern hemisphere; on the other hand, a Streaked Shearwater which is smaller than it lives in areas where it is not so windy. But if the wind profile was almost linear, the said relation between the scale of a bird and the wind strength would be reversed.

著者

Shinichiro UESAWA Susumu YAMASHITA Mitsuhiko SHIBATA Hiroyuki YOSHIDA

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.5, no.4, pp.18-00115, 2018 (Released:2018-08-15)

参考文献数

17

被引用文献数

2

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A dry method is one of fuel debris retrieval methods for decommissioning of TEPCO’s Fukushima Daiichi nuclear power station. However, the cooling of fuel debris must be fully maintained without water. Japan Atomic Energy Agency (JAEA) has evaluated the air-cooling performance of the fuel debris in the dry method by using JUPITER. Because JUPITER can represent the relocation of the corium, the unknown parameters, such as the composition and the position of the fuel debris at the RPV pedestal, can be reduced. By calculating the heat transfer of the fuel debris based on the corium relocation obtained with JUPITER, more accurate analysis of the air-cooling performance of the fuel debris in the dry method is expected. In order to evaluate the air-cooling performance of fuel debris in the dry method by using JUPITER, the validation of the free-convective heat transfer analysis of JUPITER were performed in this paper. In order to qualitatively evaluate results of JUPITER for configurations closer to experimental conditions and to decide physical values and positions to be measured in the validation, JUPITER was compared with OpenFOAM for the simple cuboid configuration which has the heating and cooling surfaces at the floor and the ceiling, respectively. The comparison proved that JUPITER can calculate the vertical temperature distribution as well as OpenFOAM on the condition of the lower heating amount. In the validation, JUPITER was compared with the heat transfer experiments of free convection in air adjacent to an upward-facing horizontal heating surface. The comparison proved that JUPITER was in good agreement with the experiment on the condition of the lower heating-surface temperature. The result indicated that JUPITER is a helpful numerical method to evaluate the free-convective heat transfer of the fuel debris in the dry method.

著者

Masahiro KANAZAKI Kai TOMISAWA Koji FUJITA Akira OYAMA Hiroki NAGAI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.14, no.3, pp.JFST0017, 2019 (Released:2019-12-19)

参考文献数

11

被引用文献数

1

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We redesigned the Mars Airplane Balloon Experiment Two (MABE-2) based on MABE-1 to improve the vehicle’s stability and controllability. Following the redesign, the MABE-2 vehicle had a larger horizontal tail volume than that of MABE-1 for improved stability performance. In addition, to further improve the stability and control characteristics, a rectangular planform was employed for the horizontal tail wing; in contrast, MABE-1 had a tapered planform. The vertical tail position of MABE-2 was moved to the end of the horizontal tail wing, because the vertical tail of MABE-1, which was positioned at the mid span of the horizontal tail wing, showed aerodynamic interaction with the horizontal tail wing. In this paper, we discussed the aerodynamic performance of a control surface based on computational fluid dynamics with variation in the deflection angle between the control surface and the horizontal tail (elevator), and we examined the effects of this redesign on longitudinal control characteristics. Numerical investigations confirmed the linear variation in the pitching moment and the aerodynamic force with the changing elevator deflection angle in MABE-2. Surface pressure observations indicated that MABE-2 shows a smooth variation in the pressure distribution with changing elevator deflection angle, while MABE-1 does not. These results demonstrate that the aerodynamic control characteristics of MABE-2 were improved in comparison to those of MABE-1.

著者

Naoki MORITA Kazuo YONEKURA Ichiro YASUZUMI Mitsuyoshi TSUNORI Gaku HASHIMOTO Hiroshi OKUDA

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Letters (ISSN:21895236)

巻号頁・発行日

vol.2, pp.16-00082, 2016 (Released:2016-03-03)

参考文献数

9

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Structural elements which have 6 degrees of freedom (DOFs) at each node, such as shell and beam elements, are widely used in structural analysis. A matrix originating from finite element method (FEM) is stored in some sparse matrix storage format with a suitable block size for the number of DOFs at each node. When both 6 DOF structural elements and general 3 DOF solid elements are employed, the sparse matrix storage format becomes complicated due to combination of different block sizes. High computational efficiency of finite element analysis has become more important in large-scale structural problems. The complicated storage format leads to deterioration of computing performance in solving linear equations by an iterative procedure, conjugate gradient (CG) iterations for example. A computational technique is required that allows us to use existing parallel linear solvers without deteriorating the performance for solving linear equation systems originating from combination of solid and structural elements. This research aims to develop 3×3 DOF blocking structural elements to enhance the computational intensity of iterative linear solver, such as the CG method. As numerical results, the proposed 3×3 DOF blocking elements have shown better performance for each CG iteration than the conventional structural elements. The computational efficiencies are 95.0% with single thread execution and 76.6% with 8-thread execution of a theoretical peak performance based on the STREAM benchmark.

著者

Seiichi SUDO Koji TSUYUKI Junji TANI

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series C Mechanical Systems, Machine Elements and Manufacturing (ISSN:13447653)

巻号頁・発行日

vol.43, no.4, pp.895-900, 2000-12-15 (Released:2008-02-18)

参考文献数

11

被引用文献数

20 26

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This paper describes detailed wing morphology of some kinds of insects. The structural properties of dragonfly, fly, and mosquito wings were studied. Microscopic observations on the insect wings were examined with a scanning electron microscope. The surface roughness of the insect wings was measured by a three-dimensional, optical shape measuring system. The roughness distribution on the wing surface was presented for some kinds of insects. Some functional principles underlying insect wing design were revealed by the measurements of surface roughness and microscopic observations.

著者

Yutaro MOTOORI Susumu GOTO

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.14, no.3, pp.JFST0016, 2019 (Released:2019-12-19)

参考文献数

16

被引用文献数

3

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Coarse-graining is indispensable for extracting a hierarchy of vortices in fully developed turbulent flow with multiscale nature. In the present study, for a high-Reynolds-number turbulent boundary layer, we employ two simple coarse-graining methods in real space; namely, a Gaussian filter and the combination of the Gaussian filters at two scales. The former corresponds to a low-pass filter of Fourier modes, while the latter corresponds to a band-pass filter. We also examine two different filter widths for the band-pass filter. Then, we show difference in the statistics of the three filtered fields. Since the velocity gradients in turbulence are mainly determined by the smallest-scale motions, vortical structures identified by the second invariant Q of the velocity gradient coarse-grained by the filters are similar. However, there is difference between low- and band-pass filtered fields in the contribution to the enstrophy production rates. This is because the production rates are determined not only by the magnitude of the strain rates but also by the alignment between the vorticity and the stretching direction. In addition, since vortices are not created in the entire system, the conditional sampling by the value of Q is essential to understand the generation mechanism of the hierarchy of vortices. The conditional analysis of the band-pass filtered fields demonstrates that small-scale vortices in the log layer are stretched by twice-larger vortices, whereas they weaken the twice-larger vortices. This observation is consistent with the picture of the energy cascade. We also show that when using the band-pass filter, these conclusions are robust irrespective of the choice of the filter width.

著者

Sorapong PAVASUPREE Supachai NGAMSINLAPASATHIAN Yoshikazu SUZUKI Susumu YOSHIKAWA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Solid Mechanics and Materials Engineering (ISSN:18809871)

巻号頁・発行日

vol.2, no.1, pp.R01-R01, 2008 (Released:2008-01-31)

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This article has been found to be a duplicate publication of their article on another journal, and thus retracted by the Editor.

著者

Vitor Mitsuo FUKUSHIGUE HAMA Wei WU Mutsunori YAGIURA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Advanced Mechanical Design, Systems, and Manufacturing (ISSN:18813054)

巻号頁・発行日

vol.12, no.3, pp.JAMDSM0072, 2018 (Released:2018-07-20)

参考文献数

29

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The overall planning process undertaken by a bus company is traditionally composed of five sub-processes: timetabling, vehicle scheduling, maintenance scheduling, crew scheduling, and crew rostering. Solving the full optimization problem is believed to be computationally intractable, and therefore in practice the five sub-processes are usually optimized in sequence. In this paper, we present a model that integrates the problems of vehicle scheduling and maintenance scheduling. The objective is to minimize the differences in mileage between buses, the total distance traveled, and the daily differences in the number of maintenance tasks. We propose a heuristic algorithm using the framework of greedy randomized adaptive search procedure (GRASP), and we improve the neighborhood search procedure by using an ordered list of possible trips. We compare the neighborhood search procedure with and without this mechanism and show that the ordered list reduces the number of neighbors to be checked by more than 95%, and it reduces the time to obtain solutions of the same or better quality by an average of 70%. Through computational experiments on instances generated from real-world data, we show that the proposed algorithm finds solutions that are as good as or better than those obtained by a commercial solver in less than 5% of the time required by the latter.

著者

田辺 実 常盤 匡 小泉 忠由

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.80, no.817, pp.DSM0274-DSM0274, 2014

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The relationship between the elements included in materials and the fire ball obtained by spark test, that is simple, has been examined by using SEM photographing of the fire ball. From experimental results, the kind of steel material could be estimated from fireballs image of SEM. The following contents would be pointed out as the results. The size of fire ball becomes large with the increase in the contained carbon. The size of alloy steels becomes about the double of fire ball of carbon steel. When nickel element is contained in a material, the surface of fire ball shows the delamination. When the many chromium components are contained the size of fire ball becomes large, and many holes occur in the fireball. The presence of molybdenum element in the steel shows the smooth texture at the surface of the fireball. The wrinkles appear at the surface of the fireball by the presence of tungsten element, and the many holes occur in the fireball. Whether the material is ductile or brittle we would be estimated from the pattern of deformation of the hole of the fire ball. The kind of material would be able to distinguish from the qualitative properties of the fire ball.

著者

古谷 正広 太田 安彦 北口 佳範 大崎 守 村井 美樹 磯貝 鉄也

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.67, no.662, pp.2625-2631, 2001

被引用文献数

3

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Compression ignition of a stoichiometric iso octane/oxygen/argon mixture was observed using a shock tube and a rapid compression machine. Reducing the compression temperature, the activation energy for the shock compression ignition fell suddenly at the critical temperature the ignition delay exceeded around 1 ms. This peculiarity could be seen in the shock compression stoichiometric methane ignition with which mixture absolutely no cool flame low-temperature reactions accompanied. Shock wave diagrams indicated that the ignition was originated not at the end of the tube but to the inside of the tube. It resulted in the smaller activation energies in the lower temperature regions. This phenomenon was not due to the difference of chemical reaction mechanisms. IIigh-speed schlieren observations using another shock tube with visualization windows have allowed us to confirm the peculiarity that the earliest ignition sites were located apart from the tube end and the ignition initiation structure would change depending on the compression temperature.

著者

Tomoaki UCHIYAMA Kenji KAWAGUCHI Toshio WAKABAYASHI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Power and Energy Systems (ISSN:18813062)

巻号頁・発行日

vol.5, no.3, pp.360-375, 2011 (Released:2011-08-30)

参考文献数

20

被引用文献数

3 8

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The purpose of this study is to investigate the effects of the consideration of simultaneous occurrence of seismically induced events in Nuclear Power Plants (NPPs) such as failures of components due to seismic stress, seismically induced fire, and seismically induced internal flooding in seismic probabilistic safety assessment(PSA). The seismic risk is estimated in terms of the Core Damage Frequency (CDF) and the CDF is comprised of occurrence frequencies of accident sequences. In this study, two analytical methods, upper bound approximation (UBA) using minimal cut sets (MCSs) and direct quantification of fault tree using Monte Carlo simulation (DQFM) are selected for comparison. The results showed that the simultaneous occurrence of seismically induced events should be reasonably considered to assess the intersection and the union of these events. In addition, the Great Eastern Japan Earthquake and the Tsunami damaged NPPs on the Pacific Coast of Eastern Japan on March 11, 2011 will be examined in this study.

著者

Chi-Kyung KIM

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)

巻号頁・発行日

vol.46, no.2, pp.103-108, 2003 (Released:2004-06-25)

参考文献数

11

被引用文献数

1 1

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The time-discontinuous Galerkin method based upon using a finite element formulation in time is derived. This method is to use the weighted residuals to treat space and time in a uniform manner and thus integrating both the spatial and temporal variations of the unknown quantities simultaneously. The approximations are continuous with respect to the space variables for each fixed time, but they admit discontinuities with respect to the time variable at each time step. Interpolation functions and weighting functions are taken to be discontinuous across inter-element boundary. This method generates a complete space-time finite element discretization which eliminates the need for any additional ordinary differential equation solver to resolve the temporal behavior of the problem. No significant instability problems and much more rapid convergence to the analytical solution were experienced in this approach than the semidiscretization method.

著者

Yutaka OKAMOTO Masafumi OKADA

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.10, no.6, pp.23-00200, 2023 (Released:2023-12-15)

参考文献数

17

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In excavation by hydraulic excavators, automation of excavation is effective in reducing the burden on operators and improving work efficiency. This paper focuses on automatic control of the weight of excavated soil. To control the weight of excavated soil, a soil dynamic model is required. However, the interaction between soil and bucket is complex and computationally expensive, making it unsuitable for real-time control. In this paper, we propose a dynamic model of excavation based on the experimental data of the weight of excavated soil and the workload done by the bucket. In addition, a differential equation that expresses the relationship between the data is derived. Based on the proposed model, a control method is also proposed to achieve the reference weight of excavated soil by changing the dragging length, assuming that the power done by the bucket during excavation is equivalent to the swept volume. Furthermore, we evaluate the effectiveness of the proposed method by excavating under several soil conditions using the proposed method.

著者

Keizo WATANABE YANUAR Hiroshi MIZUNUMA

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series B Fluids and Thermal Engineering (ISSN:13408054)

巻号頁・発行日

vol.41, no.3, pp.525-529, 1998-08-15 (Released:2008-02-18)

参考文献数

4

被引用文献数

51 55

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A real fluid does not slip at the surface of a solid boundary. Most experimental results of a Newtonian fluid satisfy with this condition. If a real fluid can slip freely over the surface of a solid boundary, how can we deduce the slip velocity. The purpose of this study is to experimentally clarify fluid slip velocity of Newtonian fluids at the duct wall. Velocity profiles of tap water and 20 wt% glycerin solution flowing in a square duct with a highly water repellent wall were measured by means of a conical hot film anemometer. Consequently, the velocity profile with the slip is measured, and the laminar drag reduction phenomena and the friction factor formula for a square duct with fluid slip at the wall have been obtained.