Kazuhiko Toshimitsu

Experimental Study of a Straight-Bladed Vertical Axis Wind Turbine With a Directed Guide Vane Row

The objective of this study is to show the effect of guide vane geometry on the performance of wind turbine. In order to overcome the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine (S-VAWT) with a directed guide vane row has been proposed and tested by the authors. According to previous studies, it was clarified that the performance of the turbine can be improved by means of the directed guide vane row. However, the guide vane geometry of S-VAWT has not been optimized so far. In order to clarify the effect of guide vane geometry, the effects of distance between the guide vanes and the number of guide vanes on power and torque coefficients were investigated in the experiments. The experimental study was carried out by a wind tunnel. The wind tunnel with a diameter of 1.8m is open jet type. The wind velocity is from 5 to 9 m/s in the experiments. The rotor has three straight blades with a profile of NACA4518 and a chord length of 100 mm, a diameter of 0.6 m and a blade height of 0.7 m. The guide vane row consists of some arc plates.Copyright

Double linearization theory for prediction of mean loading effect on cascade flutter, II: Two-dimensional supersonic cascade

Abstract In this paper an improved mathematical formulation is given of the double linearization theory for predicting the mean loading effect upon the unsteady aerodynamic force for two-dimensional vibrating cascades in subsonic flows. The double linearization theory deals with both steady and unsteady components of disturbances on the basis of a linearized approximation on the assumption that the cascade is lightly loaded and vibrating with an infinitesimal displacement amplitude. The improvement is to take account of the effect of equivalent unsteady mass sources due to motion of blades with a steady fluid density jump between the upper and lower surfaces of blades. Unsteady aerodynamic forces on lightly loaded cascades predicted by the present theory show good agreement with predictions by numerical field methods and experimental data. The dependence of the flutter boundary upon cascade design parameters is demonstrated.

Construction of virtual patient model for maxillofacial palpation training system

Abstract Palpation has been considered as one of the important diagnostic skills for doctors, which is conducted on a patient to identify the size, the consistency, and the location of a subcutaneous tumor. Accurate palpation skill often detects the cause of disease early. Even in the field of dentistry, palpation has been considered as the important diagnostic skill for dentists. By the way, any practical training of palpation against a patient did not implemented in the dental education because the patient safety has a priority more than its educational effect. Then we propose a training system for maxillofacial palpation by using virtual reality and haptic interface. The details of modeling a virtual patient model for the training system are shown in this paper, and the experimental results are also described.

Fundamental Study of a Virtual Training System for Maxillofacial Palpation

Maxillofacial palpation is a physical examination technique where face or jaw are touched with fingers to determine their shape, consistency and location. Dentists utilizes palpation to diagnose pathological condition of a patient suffered from maxillofacial diseases. This paper proposes a virtual training system for maxillofacial palpation. To provide a virtual palpation system, a basic patient model is constructed based on linear elastic finite element method. Finally the simulation results and the remained issues making the system more practical are discussed.

An experimental study of supersonic combustion with incoming high temperature pure air stream obtained by shock tunnel

An experimental study is conducted to investigate the phenomena of supersonic combustion by means of shock tunnel. By using shock tunnel, test air is compressed by reflected shock wave up to stagnation temperature of 2800 K and stagnation pressure of 0.35 MPa. Heated air is used as a reservoir gas of supersonic nozzle. Hydrogen is injected transversely through circular hole into freestream of Mach 2. Flow duration is 430 microseconds. By schlieren method and CCD UV camera, the effects of injection pressure to flowfield and the combustion were investigated.

Double linearization theory of three-dimensional cascades with vibrating blades under spanwise-nonuniform mean loading, I: Subsonic flow

Abstract The double linearization theory is extended to a supersonic straight cascade placed between parallel plane end walls, and the effect of spanwise-nonuniform mean loading upon the unsteady aerodynamic force for vibrating blades is studied. The three-dimensional version of the theory takes account of the unsteady spanwise aerodynamic force component due to spanwise nonuniformities of the mean blade loading and the vibration amplitude. The unsteady shock displacement effect on the unsteady aerodynamic force is found to be quasi-two-dimensional. Numerical examples are presented to demonstrate several features of the unsteady aerodynamic response ascribable to the effects of the spanwise-nonuniform angle of attack, camber and thickness of blades. The effect of nonuniformity of camber or thickness is larger than that of angle of attack. To attain a large steady loading on the stability boundary of the first mode bending vibration, it is advantageous to design blades with the angle of attack decreasing and the chamber and thickness increasing from hub to tip.

Effects of Chordwise Displacement and Nonrigid Section Deformation on Unsteady Aerodynamic Response of Subsonic and Supersonic Oscillating Cascades

The double linearization theory is applied to lightly loaded two-dimensional subsonic and supersonic cascades undergoing oscillation with chordwise displacement or nonrigid section deformation. Numerical examples demonstrating parametric dependence of unsteady aerodynamic work on blades are presented. The chordwise displacement can be favorable or unfavorable for stabilizing the translational oscillation, depending upon the phase difference between the chordwise and normal components of the blade motion. For supersonic cascades the role of the effect of displacement of shock reflection points on unsteady aerodynamic response is significantly enhanced by the chordwise blade motion. The unsteady aerodynamic work for nonrigid section deformation is substantially influenced by steady loading.Copyright

Improvement of Mesh Free Deforming Analysis for Maxillofacial Palpation on a Virtual Training System

Palpation is important medical diagnostic technic to make correct diagnosis of symptomatic state. It requires a lot of palpation experience under leadership of an experienced medical doctor. Hence, a palpation training system with virtual model of an affected part is useful to get better at the skill. However, there is no practical training for maxillofacial palpation in the dental education curriculum in Japan. So, it is necessary for dental students that the virtual training system is developed, which can to practice maxillofacial palpation. Then, a trial palpation training system for maxillofacial disorder is developed by using virtual reality model and haptic interface. The system is consisted of a PC and the haptic device - PHANToM Omni. A virtual affected part model is constructed from multi-CT images through commercial software. In particular, the dynamic responding virtual model and real-time analysis method through simplified mesh free method are improved. Consequently, we succeed in operation at the real-time by the palpation training system.

Development of maxillofacial palpation training system using simplified mesh free method with spring-node element

Palpation is important medical diagnostic technic to make right diagnosis of symptomatic state. It requires a lot of palpation experience under leadership of experienced medical doctors. However, there is few practical training for maxillofacial palpation in the dental education in Japan. Then, a palpation training system with virtual model of an affected part is useful to get better at the skill. The coauthor dental doctors hope to develop the virtual training system which can be used to educate dental students to undergo maxillofacial palpation. Hence, a palpation training system for maxillofacial disorder is developed using virtual reality and a haptic interface. The system is consisted of a PC and the haptic device (PHANToM Omni). In particular, it is mainly improved that elastic calculation time is reduced by simplified mesh free method. Consequently, the virtual maxillofacial palpation training system successfully works at the real-time operation.

Experimental Study of Propulsion Performance by Single-Pulse Rotating Detonation with Gaseous Fuels-Oxygen Mixtures

Abstract A rotating detonation engine (RDE) is one of candidates of aerospace engines for supersonic cruse, which is better for propulsion system than a pulse detonation engine (PDE) from the view of continuous thrust and simple structure. The propulsion performance of a proto-type RDE and a PDE by single pulse explosion with methane-oxygen is investigated. Furthermore, the performance of the RDE with acetylene-oxygen gas mixtures is investigated. Its impulse is estimated through ballistic pendulum method with maximum displacement and damping ratio. The comparison of specific impulses of the mixture gases at atmospheric pressure is shown. The specific impulses of the RDE and the PDE are almost same with methane-oxygen gas. Furthermore, the fuel-base specific impulse of the RDE with acetylene-oxygen gas is about over twice as large as one of methane-oxygen, and its maximum specific impulse is 1100 seconds.