著者

山田 大輝 武市 昇

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.68, no.1, pp.38-46, 2020 (Released:2020-02-06)

参考文献数

18

---

In this study, a model of uncertainty of estimated time of arrival on a cruise route is derived, and its effectiveness for ground-based 4D trajectory management is demonstrated. Uncertainty of estimated time of arrival inevitably increases because of fluctuations in meteorological conditions, even though the Mach number, flight altitude and direction are controlled constant. Actual flight data and numerical weather forecasts are processed to obtain a large collection of flight and meteorological conditions and flight time error. Through the law of uncertainty propagation, an uncertainty model of estimated time of arrival is derived as a function of the Mach number, flight distance, wind, and temperature. The coefficients of the model are determined through cluster analysis and linear regression analysis. It is clearly demonstrated that the proposed model can estimate the uncertainty of estimated time of arrival without underestimation or overestimation at an arbitrary flight distance, even under moderate or severe weather conditions. Through numerical analysis of a 4D trajectory management using actual track data, it has been clearly demonstrated that the proposed model is able to improve both safety and efficiency of 4D trajectory management simultaneously.

著者

山岸 聡 坂本 登 佐藤 昌之

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.61, no.1, pp.1-8, 2013 (Released:2013-10-25)

参考文献数

18

被引用文献数

2 1

---

In this paper, we propose a design method of a nonlinear optimal controller for systems with rate limited actuators which are known to cause PIO of an aircraft. The PIO prevention problem is solved as a robust stabilization problem of a servo system for pilot commands. Simulation results demonstrate that the nonlinear controller achieves faster tracking performance with less oscillation and smaller input compared with an anti-windup compensator using the H∞ method. Robustness against parameter error, observation noise and time-delay is also confirmed.

著者

久保田 勇希 佐々木 駿 向後 保雄 青木 卓哉 小笠原 俊夫 石田 雄一 山田 哲哉

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.64, no.2, pp.104-112, 2016 (Released:2016-04-05)

参考文献数

29

被引用文献数

3

---

A new lightweight ablator was fabricated by the infiltration of a polyimide resin into a porous carbon material having three-dimensional network and open cell structure. In order to evaluate the performance of the ablator, the thermal response and recession resistance were evaluated using an arc wind tunnel. These properties were discussed from the viewpoint of the cell sizes of porous carbon material. With a decrease in the cell size, internal temperature of the ablator became lower. Microstructural observations revealed that the three-dimensional network structure of the ablator, which originates from the porous carbon preform, was maintained after the heating tests. Consequently, the recession resistance was better than those of existing ablators fabricated from carbon-fiber-based preform.

著者

黒田 健 今度 史昭

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.56, no.653, pp.256-261, 2008 (Released:2008-07-01)

参考文献数

5

---

Optimal aircraft maneuver against two missiles are studied. In this paper, the problem is formulated as a nonlinear optimal control problem and solved by the steepest ascent method. In order to maximize the miss distance against two missiles simultaneously, a special type of criterion function is employed by introducing a window function. Some examples obtained by our method show reasonable aircraft optimal controls, and verify the validity of our method. Our method will be applied to pursuit-evasion and collision avoidance problems with multi-vehicles.

著者

富樫 史弥 中橋 和博 伊藤 靖 森野 裕行 岩宮 敏幸

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.48, no.556, pp.142-147, 2000-05-05 (Released:2009-07-09)

参考文献数

6

---

The use of overset concept for the unstructured grid method is relatively unexplored. However, the overset approach can extend the applicability of the unstructured grid method for real engineering problems without much efforts in code developments. Multiple moving-body problem is one of those applications. In this paper, the overset unstructured grid method is applied to a flow simulation about an experimental supersonic airplane separation from a rocket booster. Two unstructured grids, each of which covers the airplane and the rocket booster respectively, are used for the simulation. The grid around the rocket booster moves with time in the stationary grid about the airplane. The computed result clearly simulates the shock wave patterns between two bodies. Comparisons with the experimental results show good agreements in the lift and pitching moment coefficients of the airplane and booster during the separation process.

著者

中山 勝之 坂村 芳孝

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.56, no.655, pp.363-369, 2008 (Released:2008-08-27)

参考文献数

22

---

The present paper reports the result of a numerical study on efficient solution-adaptive grid refinement algorithms for simulating unsteady flows with discontinuities. We implement a flow feature detection algorithm originally developed for quadrilateral grids by Aftosmis and Kroll (AIAA Paper 91-0124, 1991) to achieve efficient adaptation for triangular grids for simulating strongly unsteady flows with moving discontinuities such as shock waves and contact discontinuities. In their algorithm, the detection of strong shock waves is isolated from that of other smooth flow features, and the threshold for grid refinement is automatically tuned based on the statistics of grids in the smooth flow feature detection step. We illustrate the performance of the algorithm with numerical results for two benchmark problems (shock tube and double Mach reflection problems) of two-dimensional unsteady flows.

著者

秋山 皓平 手塚 亜聖 砂田 保人 李家 賢一

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.57, no.671, pp.476-485, 2009 (Released:2009-12-14)

参考文献数

15

被引用文献数

1

---

This paper investigates wing aerodynamic characteristics used for bi-plane micro-air vehicles. Surface pressure distributions of two-dimensional biplane airfoils (4% cambered-plate airfoil) were measured at a chord Reynolds number of 6.4 × 104. Lift characteristics of three-dimensional biplane rectangular wings (aspect ratio of 3) were also measured at the same Reynolds number. It was indicated that the behaviors of laminar separation bubble formed both on the upper and lower airfoils/wings affects their lift characteristics. Bi-plane wings with positive stagger, i.e. protruded upper wing indicated higher maximum lift coefficient. This is caused by different behaviors of laminar separation bubble formed on the wing.

著者

近藤 夏樹 辻内 智郁 村重 敦 西村 宏貴 青木 誠 土橋 明彦 山川 榮一 青山 剛史 齊藤 茂

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.51, no.592, pp.198-206, 2003 (Released:2003-09-26)

参考文献数

16

---

A low-noise helicopter blade, AT1, was designed with the concept of reducing noise without the drop of rotor performance. In the concept, High-Speed Impulsive (HSI) noise is reduced by applying a thin airfoil in the tip region and a dog-tooth like extension in the leading-edge of the tip region. Blade-Vortex Interaction (BVI) noise is reduced by applying the extension and a strong taper near the tip end. The stall angle of the blade is increased by the effect of the vortex generated from the leading-edge extension. As a result, the drop of rotor performance caused by the thin airfoil and the reduction of rotor rotational speed is recovered. The low-noise characteristics and the performance of AT1 were evaluated by a model rotor test conducted at Deutsch Niederländischer Windkanal (DNW). It is shown that AT1 reduces HSI noise and BVI noise and has good performance in forward flight conditions. However, the improvement of performance in high-lift conditions still remains as a future problem.

著者

桑野 寛久 國中 均 中島 秀紀

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.55, no.639, pp.188-194, 2007 (Released:2007-05-10)

参考文献数

10

被引用文献数

2 2

---

Microwave discharge Hall thruster can be operated by two operating modes. The first one is “no microwave launching” mode, thus having the thruster operating as single-stage type. The other mode is “microwave launching” mode, thus having the thruster operating as double-stage type. In order to examine the influence of microwave launching mode upon the plasma condition inside the acceleration channel, as well as the relationships between thruster perform­ance and acceleration channel length, single-probe measurements and ion beam energy diagnostics in the plume were carried out. Single-probe measurements revealed the existence of dense plasma and high electron temperature region in the acceleration channel upstream due to the heating of the electrons by microwave. The variation in the discharge current characteristic due to the difference in acceleration channel length was not significant. As for discharge current, double-stage operation always results in a lower value compared to the value at the single-stage operation. Ion beam current was always higher at double-stage operation compared to the value at single-stage operation. Voltage utilization efficiency has improved as the channel length became short with microwave launching.

著者

大坂 淳 瓜生田 義貴 今村 宰 山下 清孝 高橋 周平 津江 光洋 河野 通方

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.55, no.637, pp.98-103, 2007

被引用文献数

1 3

---

An experimental research on supersonic combustion of kerosene in a model scramjet combustor has been conducted. Kerosene was injected normally into a Mach 2 by three types of methods. First, liquid kerosene was directly injected. In comparison with hydrogen, combustion did not take place at low total temperature or in the fuel lean condition. Secondly, “effervescent atomization” method was used. Effervescent atomization method could control penetration height and mass flow rate independently, and improve ignition limits of liquid kerosene. Finally, gaseous kerosene was used. While only intensive combustion mode and choke mode were observed when liquid kerosene was used, existence of transition mode was observed when gaseous kerosene was used.

著者

山川 宏 小川 博之 藤田 和央 野中 聡 澤井 秀次郎 國中 均 船木 一幸 大津 広敬 中山 宜典

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.52, no.603, pp.148-152, 2004 (Released:2004-05-31)

参考文献数

4

被引用文献数

5 6

---

A magneto-plasma sail produces the propulsive force due to the interaction between the artificial magnetic field around a spacecraft inflated by the plasma and the solar wind erupted from the Sun. The inflation of the magnetic field by the plasma was proposed by a group of the University of Washington and the basic research has just started. This paper summarizes the characteristics of the magneto plasma sail by comparing with the other low-thrust propulsion systems, and investigates its potential application to near future planetary missions. Finally, an engineering satellite to demonstrate the magneto-plasma sail is proposed as a first step.

著者

山田 剛治 鈴木 俊之 高柳 大樹 藤田 和央

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.57, no.670, pp.426-436, 2009 (Released:2009-11-25)

参考文献数

22

被引用文献数

1 1

---

A free piston double diaphragm shock tube with 70 × 70mm cross-section at test section was newly developed for the purpose of investigating nonequilibrium phenomena behind a shock wave. This paper presents the performance of the shock tube and the measurement system newly developed. Experimental investigation to clarify its characteristics was conducted for various operational parameters, such a rupture pressure of the first diaphragm and initial pressures of the low pressure tube, the high pressure tube, and the compression tube. Based on the characteristics experiment, a performance map of the shock tube was obtained by changing the operation parameters. The result shows that the shock tube is capable of generating the shock layer corresponding to the super orbital reentry flight conditions. The newly developed measurement system enables us to obtain the spatial distribution of spectra behind a shock wave with high spatial and time resolution. A description of the measurement system and typical examples of the measured spectra are presented.

著者

海老沼 拓史 中須賀 真一

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.54, no.635, pp.542-548, 2006 (Released:2006-12-25)

参考文献数

9

被引用文献数

2 2

---

An increasing number of small satellites and hybrid rockets are proposed for miscellaneous space applications, many of which assume the use of Global Positioning System (GPS) for positioning. Some of those platforms are designed and developed by university students and require very low power consumption and also low cost. This paper describes the adaptation of small GPS receivers and open source receiver firmware for space and high dynamics applications, including software performance validation using a GPS signal simulator.

著者

井藤 創 本田 博一

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.58, no.679, pp.226-232, 2010 (Released:2010-08-27)

参考文献数

19

---

This paper describes results of an exploratory study to investigate the capability of a passive approach for controlling the characteristic spanwise length of Görtler vortices generated in hypersonic flows: a serrated leading edge. Heat transfer, pressure measurements, encapsulated thermochromic liquid crystal, schlieren and glow spark visualizations were conducted with a flat plate/ramp model whose leading edge had a triangular wave shape in a gun tunnel at Mach number 10. Effect of wavelength Λ of the triangular waves on downstream flows was studied. Aerodynamic heating patterns observed with the liquid crystal confirmed that the vortex wavelength was equal to Λ. This was also supported by the spark results that filamentary bright lines perpendicular to an installed line-anode parallel to the spanwise direction at the ramp surface emerged at intervals of Λ. Phase lag was observed only between heat transfer data measured in the spanwise direction, which suggests that the vortex structure existed in the reattaching boundary layers. Pressure distribution in the streamwise direction was similar among all of the Λ tested. In contrast, the heat transfer data points exhibited a large scatter and the peak heating value for the finite Λ was somewhat larger than that for the infinite Λ. Schlieren results indicated that the appropriate Λ can mitigate flow separation.

著者

満武 勝嗣 東野 伸一郎

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.58, no.677, pp.153-163, 2010 (Released:2010-07-23)

参考文献数

10

被引用文献数

3 5

---

The authors have proposed the A*-EC hybrid path planning method which can generate a 3D flight path quickly considering terrain and obstacle avoidance. This paper proposes two methods to improve its calculation time in order to apply it to a larger scale problem in real time. Using the two methods, the calculation time reduces approximately from half to quarter. The authors measure the calculation times to examine the performance of the improved A*-EC method by changing the number of waypoints and ``nodes'' which are the apexes of the 3D cells expressing terrain and obstacles. Calculation time is about 10—100 seconds in case of 50—100 waypoints and 2000—7500 nodes. The authors apply the method to a large scale problem in which there are 61 waypoints and about 7000 nodes, and actual topological information and recorded weather information are used as obstacles. The simulation result shows the method can be used in real time.

著者

神永 晋 富岡 定毅 山岬 裕之

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.53, no.623, pp.554-561, 2005 (Released:2006-01-06)

参考文献数

16

被引用文献数

1

---

Flow behavior and thrust performance of MHD energy bypass scramjet engine was examined numerically. MHD generator was placed at the isolator to enhance the flow compression. Kinetic energy was converted to electrical energy in the MHD generator. Extracted electrical energy was consumed at the MHD accelerator placed at the downstream of the combustor. When MHD energy bypass system was used, the flow was decelerated and compressed in the MHD generator. Effect of velocity and Mach number on wall friction was analyzed and decrease of friction force was pointed out. Also, high pressure in the combustor resulted in increase of pressure contribution to net thrust. Despite of positive effects, decelerating Lorentz force in the MHD generator was comparably large and no significant difference in net thrust performance is observed.

著者

平川 美晴 中北 正人

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.47, no.546, pp.267-271, 1999-07-05 (Released:2009-07-09)

参考文献数

6

---

The performance of the ion thruster depends on the discharge performance and the beam extraction, the former of which is significantly effected by the electron property such as density and energy, since ions are produced by ionization collisions between neutral atoms and electrons. In the microwave ion thruster, the discharge owes to the electron cyclotron resonance (ECR). Thus, the electron phenomenon in the microwave discharge chamber was numerically investigated by the particle simulation method. In our model, the electromagnetic wave is polarized circularly and propagates in the axial direction and electrons are moved in the microwave and static magnetic fields, colliding with neutral particles. Collision processes are taken into account by the Monte Carlo method. This simulation results show that some electrons can be heated enough to cause ionization collisions and that the density and energy distributions are peculiar to the microwave ion thrusters.

著者

佐藤 昌之 村岡 浩治

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.61, no.4, pp.110-118, 2013 (Released:2013-10-25)

参考文献数

15

被引用文献数

3 5

---

This paper is concerned with the flight controller design of Quad Tilt Wing (QTW) Unmanned Aerial Vehicle (UAV) which has Vertical Take-Off and Landing (VTOL) capability as well as high speed cruise performance. The flight controller is composed of Stability Augmentation System (SAS), which feedbacks angular velocity, and Control Augmentation System (CAS), which feedbacks the difference between attitude commands and current attitude angles. The gains of S/CAS are both scheduled by the tilt angle of the main wings of the QTWUAV since its airspeed and flight dynamics drastically change in accordance with the tilt angle. The S/CAS are designed by three steps; we first select several design points, then design the controller gains at those design points, and finally connect the gains by linear interpolation. In the design process of the controller gains, perturbed models are introduced in addition to the nominal models, and common gains for those models are designed to ensure robust control performance against modeling errors. Full transition flight from vertical take-off to horizontal cruise was successfully accomplished using our controllers.

著者

長谷川 裕晃 塚本 義明 花田 忠之 田北 勝彦

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.50, no.581, pp.231-231, 2002 (Released:2003-09-02)

参考文献数

6

---

The application of ceramic components in gas turbine engines enables the improvement of the power output and the efficiency of gas turbines by increasing the turbine inlet temperature. The high temperature properties of the ceramic materials offer the potential of higher turbine operating temperatures with no cooling techniques and therefore the ceramic components with higher temperature limits are becoming more attractive. In this study, the ceramic turbine wheel is applied in the aircraft gas turbine engine and the engine testing is demonstrated under full load operating conditions. The successful testing of the ceramic turbine components in the aircraft gas turbine engine has been accomplished. The test results indicate that the ceramic turbine wheel is capable of operating under the high thermal shock condition of fast starting to full speed. Furthermore, the adoption of some new ceramic turbine design concepts is proposed in actual use for aircraft ceramic turbine engines.

著者

小池 勝 石井 満

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.57, no.663, pp.166-174, 2009 (Released:2009-04-30)

参考文献数

7

被引用文献数

1

---

In recent years Micro Air Vehicles (MAV) for disaster aerial video are developed vigorously. In order to improve aerodynamic performance of MAV wing performance in low Reynolds numbers (Re) need to be improved, but research on the theme are very rare. In category of Hand Launch Glider, a kind of model aircraft, glide performance are competed, as a result high performance airfoils in Re is around 20,000 are developed. Therefore for MAV's aerodynamic performance improvement airfoils of Hand Launch Gliders should be referred and aerodynamic characteristics of the airfoils desired to be studied. So in this research, aerodynamic characteristics of the gliders are measured in wind tunnel. And also consistency between wind tunnel test and glide test in calm air is examined to confirm reliability of wind tunnel test. Comparison of different airfoils and flow visualization are also performed.