vol.18 (2005)

Bulletin of Computational Science Research Center
Vol.18, 2005 ISSN 1347-6726 Published March 22, 2005

Numerical Analysis of Flow within Ultra Micro Centrifugal Compressor
Junpei Yamamoto, Tomohito Akiyama, Ryoichi Eto, Shimpei Mizuki, Hoshio Tsujita
PDF   Abstract
In recent years, a lot of experimental and numerical investigations have been made for the micro centrifugal compressor system used as the mobile electrical power source, the electric distributed energy source, the gas turbine for micro plane and so on. However, the downsizing of the centrifugal compressor system makes impossible to measure the internal flow in the rotating impeller experimentally. In the present study, the internal flow in the micro centrifugal impeller was particularly revealed by computational fluid dynamics in order to realize the micro centrifugal compressor for a micro gas turbine system.
Effect of Blade Profile and TIP Clearance Size on Aerodynamic Performance of Ultra -Highly Loaded Turbine Cascade
Kouji Ishihara, Shimpei Mizuki, Hoshio Tsujita
PDF   Abstract
The increase of blade loading of a turbine cascade makes it possible to reduce the number of blades and stages, and consequently to decrease both the weights and the costs for manufacturing and main tenance. However, the strong secondary flow appears in such highly loaded turbine cascades due to the high turning angles and reduces the efficiencies. In the present study, the effects of the profile of the suction surface and the tip clearance (TCL) on the aerodynamic performance of a stationary linear ultra-highly loaded turbine cascade(UHLTC), which will be used for the future gas turbine engines of hypersonic transport, were investigated numerically.
Flow around Two Circular Cylinders in Tandem Arrangement
Yuichi Tanaka, Shimpei Mizuki, Hoshio Tsujita
PDF   Abstract
A lot of studies have been made for the flow-induced oscillation around a circular cylinder. However, the study for two or more cylinders has been seldom. For the velocity region with out the oscillation for single cylinder, the tandem cylinders generate oscillations. The mechanism for this type of oscillations has not been clarified yet. In this point of view, the flow around tandem cylinders is analyzed numerically based on the experimental results of flow visualizations using P.I.V.
Ballistic Limit Velocity of Debris Bumper Shield Material(A6061-T6)
Kengo Kanemoto, Masahide Katayama, Kazuyoshi Arai
PDF   Abstract
The ballistic limit velocity and failure mechanism of aluminum alloy A6061-T6, which is outer bumper of Whipple shield, are investigated at space debris impact velocities of 1km/s or less. Numerical simulations using Autodyn 2D hydrocode and perforation tests are carried out using various nose-shaped projectiles and debris bumper shields with various thickness.
Numerical Analysis of Flow in Bubble Eliminator
- Evaluation for Removal Performance of Bubbles -

Yuuki Ishida, Yutaka Tanaka, Ryushi Suzuki
PDF   Abstract
Air entrainment in working fluids has greatly detrimental effects on function and lifetime of the fluid power components and systems. This may cause major problems such as cavitation and aeration, noise generation and vibration, oil temperature rise, and deterioration of oil quality. Especially, when bubbles in oil are compressed adiabatically at the high pressure in a pump, the temperature of bubble rise sharply and the surrounding fluid temperature also rise. Thus, it is important to eliminate the air bubbles from the oil to preserve oil quality, system performance and to avoid possible damage of the components. One of the authors has developed a newly device using swirl flow for bubble elimination capable of eliminating bubbles and of decreasing dissolved gases. This device is called the Bubble Eliminator. In this paper, numerical analysis has been performed for clarifying swirl flow characteristics and pressure distributions. The numerical analysis of two-phase flows has also been carried out to investigate the performance of bubble removal. As results of the numerical simulation, we will design a more efficient type of bubble eliminator.
Tele-Operated Hydraulic Excavator with Virtual Environment
Hirokuni Beppu, Taichi Mizuno, Yutaka Tanaka
PDF   Abstract
In this paper, it proposes a remote-controlled interface that uses Augmented Reality instead of conventional remote control that uses the camera image. This interface offers a high presence by moving the camera according to the angle of operator’s head. As the example of applying the remote control of the construction machinery, it is experimentally verified that time delay generated by data transfer are compensated with the interface using Augmented Reality.
Sound and Vibration Simulation of the Golf Club
Takahiro hattori, Nobuhiro Matsumura, Mitsuo Iwahara, Akio Nagamatsu
PDF   Abstract
The discrimination can not be attempted concerning the flight-distance, since the standard by NPO (the international park golf association ) has determined the performance of the golf club as “that the difference of the flight-distance in the comparison with the standard club is within ±3%” at present. Therefore, in order to enjoy the golf for the good feeling recently, it begins to be asking swing sound of golf club and collision noise with the ball for the merchandizing. In this study, the latter be taken up.
Research on Strength and Vibration Characteristic of Sirocco Fan
Go Sakurai, Jun Odate, Mitsuo Iwahara, Akio Nagamatsu
PDF   Abstract
For the product to clarify the stress and the character frequency etc. of the product before it is possible to do and to work measures and to solve it in a permissible stress etc. it, the use fan case and frange. theory mode analysis., are analyzed, this research, it clarifies for strength and the vibration characteristic of fan case, the flange, and the Sirocco fan.
Research of Tone Quality by Structural Optimization of Cymbals
Katsuya Kumeda, Yoshiaki Shoda, Mitsuo Iwahara, Akio Nagamatsu
PDF   Abstract
We targeted in the research on tone quality, and adopted the percussion instrument cymbals. To model cymbals, the calculation mode was analyzed first as the experiment mode analysis. After cymbals were modeled, the design condition was tried, and, board thickness and the restriction condition were assumed to be a character frequency, and structural optimization for the cymbals tone quality improvement was tried. Moreover, to confirm whether tone quality had improved by structural optimization, the radiation sound was calculated.
The Analysis of Vibration and Noise Characteristic of Stepping Motor
Takeshi Kobita, Kunisada Hashimoto, Mitsuo Iwahara, Akio Nagamatsu, Gaku Minorikawa
PDF   Abstract
The noise generated from the stepping motor was recorded, and the acoustic analysis was done. By changing rotational frequency, the experiment recorded the noise generated from the motor surface. Simultaneously, measuring the surface vibration, vibration characteristic of stepping motor was clarified for the experimental modal analysis. The modal property is identified in experiment, fixing the acceleration pickup in the motor surface, by getting response of 24 points, and the phenomenon in the motor operation is explained.
Experiment Modal Analysis and Structural Optimization of Tennis Racket
Kaoru Suzuki, Jun Odate, Mitsuo Iwahara, Akio Nagamatsu
PDF   Abstract
The purpose of this study is that clarifies and improves the vibration characteristic of tennis racket by experiment and calculation. First, the following are obtained by the experimental mode analysis : Natural frequency and natural mode, modal damping ratio of tennis racket. Next, the drop test of the ball is carried out in order to reproduce the phenomenon in striking the ball actually, and it is compared with the experimental mode analysis. On the basis of the result of experimental mode analysis and drop test of the ball, resonance point and anti-resonance point were calculated according to the general-purpose finite element program, and the structural optimization using each sensitivity was carried out.
The Research of Vibration Characteristic and Structural Optimization of Tennis Rackets by the Modal Analysis
Jun Odate, Mitsuo Iwahara, Kaoru Suzuki, Akio Nagamatsu
PDF   Abstract
The purpose of this research is that clarifies and improves the vibration characteristic by experiment and calculation in order to do the countermeasure of the vibration problem by predicting in the design development and to shorten the development time. This study compares and examines the vibration in the case in which the ball was struck actually and was dropped with the experimental mode analysis using familiarly used tennis racket. It was proven that most large vibration had been generated at the first mode. It was possible to make the excitation response point to be a knot at the mode by the structural optimization of plate thickness and the mass given to the circumference.
Monte Carlo Simulation of Lennard-Jones Molecular System
Tomofumi Maruyama, Yosuke Kataoka
PDF   Abstract
The program of the Monte Carlo simulation of a Metropolis method was developed on Lennard-Jones molecular system. The initial configuration was FCC structure. The vapor, liquid, solid and cluster phases were simulated by the periodic boundary condition. The self-diffusion coefficient was estimated by the mean square displacement with some assumption on the average displacement.
Molecular Dynamics Simulation on Square Well Function System
Juntaro Takeuchi, Yosuke Kataoka
PDF   Abstract
We carried out molecular dynamics simulation on square well function system. In this system, the fluid-solid phase translation and vapor-liquid phase transition were confirmed from the pressure, average potential energy and self diffusion coefficient.
Physical Properties and Phase Transition in Carbon Crystal
Kentarou Aoki, Yosuke Kataoka
PDF   Abstract
We used application program“Materials Explorer 3.0 Professional”for present molecular dynamics simulation. The solid phase with the diamond structure changed to the liquid state by heating. The vaporization was detected atthe very high temperature. However, phase transiti on from the diamond to graphite was not observed.
Reconstruction of Projection Data with Legendre Polynomials in Compton CT
Yoshimi Nakayama, Koichi Ogawa
PDF   Abstract
This paper investigates Compton computed tomography(CT) imaging. Compton CT has an advantage in detection efficiency of gamma rays compared with the conventional data acquisition method with a collimator. However we have to decide the direction of gamma rays with the information in two detectors used in Compton CT. To solve the problem we implemented Parra’s analytical reconstruction method with Legendre polynomials. Simulation results showed that the reconstructed projection data with this analytical method were superior to the conventional data collection method with a collimator.
Numerical Simulation Analysis of Thermal Environment of Vernacular Architecture
- About The House with Wind Catchers -

Keiko Sugawara,Kiyotaka Deguchi,Hidenobu Jinnai,Naomi Ando
PDF   Abstract
In this paper an analysis is made about thermal environment of the vernacular architectures in hot arid region. Outside temperature of hot arid regions is a high degree effect of solar radiation, a high rate of radiation loss to the sky during the night. And the wind fixed patterns of diurnal and seasonal. People have adopted a way of life highly influenced by the climate. They made use of the prevailing summer winds, developed wind catchers. They made use of adobe walls and a small number of doors and windows for their rooms. And people place a fountain or a basin of still water under the wind catcher to cool the wind flowing into the room by evaporation. These devices were required to provide air cooling, at increased rates of airflow, sufficient to meet the conditions of both hygiene and thermal comfort. We examined the thermal environment in a building by CFD, paying attention to a wind catcher. Consequently, it checked that wind catcher was carrying the fresh wind in the room. And it turns out that the wall with large heat capacity has the role which makes change of room temperature small. The maximum temperature of the indoor was about 4~5 degree lower than the outside, and the time of the peak shifted for about 3~4 hours. And temperature of the place around a fountain in a room was about 3 degree lower than another place in the room.
Study on Analysis of Brittle Material by Discrete Element Model
Jun Kato, Junya Aono, Nagayuki Yoshida
PDF   Abstract
The soil and structure shows an elastic property in the small displacement. On the other hand, the phenomena of the discrete particle system including liquefaction dominates the almost domain of the larger displacement. Therefore we take a new approach on the whole domain of deformation from an elastic continuity to discrete particles. It consists of corner springs for representing an effect of the Poisson’s ratio and shear deformation and straight elements, which are connected to concentrated masses.
Analytical Study on Temperature Distribution and Thermal Stress of Concrete in Tunnel Fire
Toshiaki Mizobuchi, Ryousuke Hayashi
PDF   Abstract
It is known that a surface of tunnel lining concrete is exposed to high temperature, when the fire was generated in enclosed space such as tunnels. Then, the computational fluid dynamics analysis was carried out to estimate about concrete damages caused by fire. The analysis was carried out from the viewpoint of size of heat sources and existence of wind. As the results, it was made clear that concrete just above fire source was exposed to high temperature, when there is no wind. Also, it was made clear that the range exposed to high temperature enlarged, though temperature just above fire source in case when the wind blows, became lowers than that in case when there is no wind.
Estimation of the Effects of Storage and Infiltration Facility Systems by Runoff Analysis Based on GIS
Ryo Yamazaki, Yasumiti Oka, Koji Kodera
PDF   Abstract
This study aims to clarify the quantitative effects of storage and infiltration facility systems in urbanized basins, by using a distributed runoff model based on the kinematic wave method. The effects of the storage and infiltration facility systems on flood mitigation were estimated quantitatively. In addition, the authors examined not only the validity of a method to lump a general kinematic wave equation of the slope runoff system by sensitive analysis, but also its applicability to small urbanized basins which have different characteristics. In conclusion, the improved runoff model which incorporates the interflow component in a synthesized manner shows a successful performance.
A Study of Visualization Methodology of the 3D Magnetic Field Vectors
Naoki Fujieda, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
Visualization of the magnetic field distributions radiated from various electronic/electrical devices makes it possible to evaluate the magnetic field sources, i.e. current distributions. The magnetic field sources distributions reveal to the soundness of the electrical/ electronic devices. According this methodology, it may be possible to work out a fully automatic inspection system of the electrical/ electronic devices in a factory line. However, in order to realize this system, we have to solve to various serious difficult problems. One of the most basic and important problems is the visualizing methodology of magnetic fields, i.e. how to visualize the vector fields as the color images. In the present paper, we propose a deterministic method, which enable us to the unique visualize vector field images as the color images. Applying our color image cognition methodology to these vector field images suggests that our vector field visualization method has various possibilities for the study of physical vector fields not only the magnetic fields.
Visualization of Magnetic Fields around Power Supplies Utilizing Film Type Transformer
Yu Usuda, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
Modern microelectronics has made it possible to work out a lot of many small electronics, such as electronic calculator, radio, notebook computer and so on. Even though the electronic parts processing the electronic signals could be minimized, it is difficult to minimize the power supplier because of magnetic elements. To overcome this difficulty, we are now developing the power supplier without any magnetic elements. In this power supplier, coreless film transformer is employed instead of conventional transformers. Coreless film transformer enables us to work out an extremely lightweight power supplier but causes the other problem, i.e., magnetic field radiation around the power supplier. To examine this problem, this paper had tried to visualize the magnetic field distributions above a film transformer.
Estimation of Thermal Conductivity by Equivalent Characteristic Value
Kensaku Kawamura, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
Previously, we have proposed a new methodology, which makes it possible to extract the physical properties from the visualized magnetic domains in ferromagnetic materials. This new approach to the sequential magnetic images is based on the modal analysis solution vector of initial value problems. In this paper, we apply this approach to the thermal infrared dynamic image in order to extract the physical parameters as well as regularity that dominate the dynamics of thermal distribution. As a result, it was difficult to extract the physical parameters as well as regularity dominating the dynamics of thermal distribution, because of complex heating and cooling conditions. However, it has been found that only few images are required to recover the precise infrared images by means of the equivalent characteristic values. Furthermore, applying the modal wavelets analysis to the infrared images well visualizes the heating situations.
Light Source Image Analysis by Time Series Frequency Characteristic
Kazuo Maruyama, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
Most of the natural phenomena include a time fluctuating component. Frequency analysis of this time fluctuation component leads to the famous “1/f fluctuation” characteristic that gives mental as well as psychological relaxation effects to human. Because of wide spreading electrical power supply, modern residence removes the combustion utilities and installs much electricity. In this paper, our target is to propose the method of frequency characteristic extraction from various lighting sources, e.g. candle, fluorescent light, electrical lump and liquid crystal diode. As a result, one of the methods proposed in this paper enables us to extract major frequency characteristic of lighting sources. The other one makes it possible to analysis the precise frequency characteristic of lighting sources.
A Method of Inverse Analysis along with Current Presumption from the Locally Measured Magnetic Field Distributions
Yukihiko Anabuki, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
Previously, we have proposed the weighted inverse method (WIM in short) in order to solve the inverse source problems in electromagnetic as well as radioactive fields. WIM is one of the generalizations of a least norm type solution strategy. Thereby, it is essentially required to compute an inverse matrix. When confronting to an ill-posed system matrix in WIM approach, it is difficult to obtain a good solution vector. In order to overcome this difficulty, this paper proposes a new approach, which employs the iterative solution methods for ill-posed linear system of equations. In the present paper, we have applied the two iterative solution methods, one is well known conjugate gradient method and the other is the generalized vector sampled pattern matching method. WIM approach along with the iterative solution method is called a hybrid method. Also, it is shown that apply this hybrid method to the simulation and practical models has yielded good solution compared with those of normal WIM approach.
Visualization of Magnetic Sensor Signal and its Application
Tatsuya Yamashita, Seiji Hayano, Yoshifuru Saito, Kiyoshi Horii
PDF   Abstract
In recent years, wide spreading use of microprocessors changes various apparatus as well as instruments into the smart functional products, dramatically. Even if the most high performance microprocessors and high speed memory is exploited; it is essential to exploit the high performance sensors which give original information of the computer instructions. High sensibility, toughness to the mechanical and environmental conditions such as stress, temperature and humidity are required to any types of sensors. Magnetic sensor is classified into two major categories. One is the semiconductor type, e.g. Hall sensor, and the other is sensing or picking up coil type. As is well known fact any types of semiconductor elements are greatly dominated by environmental temperature, and also depended on the mechanical stress. On the other side, sensing or picking up coil type magnetic sensor has reasonable tough properties to the mechanical and environmental conditions, even though they do not have high sensibility. In the present paper, we propose two types of magnetic sensors in order to sense the metallic materials. Our magnetic sensors belong to the sensing or picking up coil type, and are further classified into active and passive types. Proto type of these sensors is exploited and initial experiment is carried out.
Dynamic Image Cognition by means of Discrete Taylor Series Expansion
Tohru Kosugiyama, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
Most of the conventional image cognition methodologies are based on the geometrical singular points extraction of the target images. In human face image cognition, it is proposed that the method of discriminating the ratio of the distance between eyeballs and a mouth etc. as characteristics of each face information. This recognizing method has problems such as a definition or extracting method of the singular points, and change of the singular point distribution by change of facial expression. In order to overcome these difficulties, we have previously proposed a new image cognition methodology based on the color information extracting strategy. In the previous paper, we have reported that the image cognition method based on the color information which composing each of the target images could recognize in fairly good accuracy. Furthermore, it has been reported already that this method is generalized to the dynamic images cognition. As a result, it has been reported that the dynamic images was possible to recognize more precisely than static image. In this paper, we propose the method of extracting the time variations of the color information by means of the finite differences. It is shown that this new methodology makes it possible to cognize the target objects having any background images.
Visualization of Time Domain Signals and Signal Cognition
Kimura Yuji, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
Previously, we have proposed a full automatic metallic cans classification device along with the magnetic sensor signal visualization. In this paper, we have carried out more practical experiments along with this device. In order to work out a practically usable full automatic metallic cans classification device, it should be considered that the target cans should be processed with more degree of input freedom, i. e. , free falling cans should be cognized and classified in the device. To overcome this difficulty, we have exploited a multi-stage magnetic sensor system and carried out a sequential systematic experimental works. As a result, it is revealed that simple extension from the previous system to the multi-sensor system could be cognized and classified the tested target cans in a most high accuracy. Thus, we have succeeded in developing the second stage of the full automatic metallic cans classification device.
Visualization of Conductivity Distribution by Electrical Impedance Method and Its Experimental Verification
Eiichi Otogawa, Seiji Hayano, Yoshifuru Saito
PDF   Abstract
With the developments of modern high-speed computer, X-ray tomography and MRI are widely used as a deterministic tool of medical diagnos is. On the other side, EIT (Electrical Impedance Tomography) is now developing mainly for industrial use. Fundamental difference between them is that MRI or X-ray tomography needs not to handle the functional measured data, but EIT is based on the functional nature of the measurable data. Namely, EIT requires a solution of ill-posed system equations but MRI or X-ray tomography does not require the solution of such the ill-posed system equations. In the present paper, we propose one of the most reliable solution methodologies accompanying with EIT development.
Attendance System include Face Image by Web Environment
Norimichi Ishida
PDF   Abstract
The use of web-environment at the information communication system has become increasingly important to access the required information with campus life. This application is depend on network systems. As one of the application of the network, we made “attendance system” add image file by Perl langage in this year. Students are click from own note PC via information terminal on class room. Students need only student ID number to input into seat on terminal display. As the result, teacher can check on face image correspond to name and recognition with attendance student. This is first step in the interactive education program.
Data Handling for the Magnetic Vector Field by the Wavelets
Sawa Matsuyama
PDF   Abstract
One of the distinguished properties of the discrete wavelets transform is that the major dominant factors can be extracted from the data. We have applied this property to the data compression and reducing the noise in measured data. In the present paper, we apply the discrete wavelets transform to the three dimensional-magnetic fields measured over a switching regulator. The measured magnetic fields are the three-dimensional in space and time dependents. A discrete wavelets transform always requires a number of target data composed of a power of 2, we propose here a novel approach based on Fourier transform to overcome this difficulty without loosing any original data information. A key idea is simple but effective because it exactly keeps all of the frequency components comprising the target data. We have tried to compress the magnetic vector field data by the multiresolution analysis using three dimensional discrete wavelets transform. The analysis indicates a high recovery ratio between the raw data and compressed data when the number of the data decreases even one sixty-fourth of number of the original data. As a result, several examples demonstrate the usefulness of our new method to work out the visual communication tools.