著者

香山 寛人 汪 運鵬 小澤 啓伺 土井 克則 中村 佳朗

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 = Journal of the Japan Society for Aeronautical and Space Sciences (ISSN:13446460)

巻号頁・発行日

vol.60, no.2, pp.74-79, 2012-04-05

参考文献数

12

被引用文献数

1

---

The space transportation system will need advanced abort systems to secure crew against serious accidents. Here this study deals with the capsule-type space transportation systems with a Launch Abort System (LAS). This system is composed of a conic capsule as a Launch Abort Vehicle (LAV) and a cylindrical rocket as a Service Module (SM), and the capsule is moved away from the rocket by supersonic aerodynamic interactions in an emergency. We propose a method to improve the performance of the LAV by installing fences at the edges of surfaces on the rocket and capsule sides. Their effects were investigated by experimental measurements and numerical simulations. Experimental results show that the fences on the rocket and capsule surfaces increase the aerodynamic thrust force on the capsule by 70% in a certain clearance between the capsule and rocket. Computational results show the detailed flow fields where the centripetal flow near the surface on the rocket side is induced by the fence on the rocket side and the centrifugal flow near the surface on the capsule side is blocked by the fence on the capsule side. These results can confirm favorable effects of the fences on the performance of the LAS.

著者

榊 和樹 角銅 洋実 中谷 辰爾 津江 光洋 五十地 輝 鈴木 恭兵 牧野 一憲 平岩 徹夫

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.63, no.6, pp.271-278, 2015

---

The pintle injector is one of the most promising candidate for propellant injection systems of liquid rocket engine combustors due to the throttling capability and simple structure. However, combustion characteristics of pintle injectors are still unclear. Therefore, combustion experiments are conducted for an ethanol/liquid oxygen rocket engine combustor with a planar pintle injector which simulates the injection configuration of a pintle injector and enables optical measurements at <I>Pc</I>=0.40MPa and O/F=1.08-1.56. Direct images of the flame structure and CH chemiluminesence are observed through an optical window using high speed imaging techniques. Backlit images of the spray structure are observed. Strong CH chemiluminescence is observed in the vicinity of the impinging point of the two propellants. Luminous flames are observed in the vicinity of the faceplate and the upper wall of the combustor. It is observed that atomization process of the planar pintle injector proceeds two-dimensionally unlike conventional impinging injectors. A periodic atomization behavior is observed with the frequency of approximately 700Hz, being equal to the frequency of the Kelvin-Helmholtz instability.

著者

河邉 博康

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.629, pp.250-256, 2006 (Released:2006-07-20)

参考文献数

18

---

The wings formation flight is studied by means of theoretical aerodynamics. Each wing is modeled using the horseshoe vortex. In formation flight each wing flies in an upwash field generated by all other wings of the formation, and consequently its flight power decreases. In V formation flight the wing in a central position has a smaller local flight power reduction, while in U formation flight the local flight power reduction of each wing remains equal. In the case of a long range flight, the optimum shape is not V formation, but U formation flight. It has turned out that the value of a local flight power reduction in V formation flight is equal to that in U formation flight when the leader wing of V formation shifts to the position of a follower wing.

著者

金崎 雅博 四谷 智義 奈良 拓矢 松島 紀佐

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.59, no.684, pp.24-26, 2011 (Released:2011-03-03)

参考文献数

4

被引用文献数

1

---

The original PARSEC (PARametric SECtion) method can satisfactorily solve the optimization problems involving transonic airfoils by using a few design variables. However, it is difficult to apply this method to the design of airfoils under other conditions such as supersonic flow and low Reynolds number flow. To solve various airfoil design problems by using a few design variables and the PARSEC representation, a modified PARSEC representation is proposed. The capability of the proposed modified representation to solve unknown real-world design problems is investigated; the proposed representation is used along with multi-objective genetic algorithms to solve two types of problems. One is the design of a conventional transonic airfoil that is to be used in the Earth's atmosphere; the other is the design of an airfoil that is to be used in the Martian atmosphere. To evaluate the aerodynamic performance of the airfoils, the structured Navier-Stokes solver is used. The results indicate that better solutions can be obtained by using the proposed PARSEC modification than by using the original PARSEC representation, especially in the Martian atmosphere.

著者

土井 克則 Mohd FADHLI 川島 渉 中村 佳朗

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 = Journal of the Japan Society for Aeronautical and Space Sciences (ISSN:13446460)

巻号頁・発行日

vol.59, no.693, pp.273-280, 2011-10-05

参考文献数

14

被引用文献数

3

---

A boomerang thrown properly into the air can fly in an elliptical path and return to the point of origin. In this study, such a motion of the boomerang was numerically simulated to clarify the mechanism of the motion. The simulation was conducted by the double CFD method which is the coupling method of the computational fluid dynamics and the computational flight dynamics. We considered the case that a small flat boomerang was thrown with a translational and a rotational velocity, an angle of the translational velocity from a horizontal plane, and no roll angle. Results showed that the boomerang lifted and traveled in a path with changing roll and pitch angles due to a pressure distribution on its surface, and returned to a point near the origin. Furthermore, an experiment was performed to confirm the validity of the computational results, and the experimental result was qualitatively corresponding to the computational results.

著者

福田 盛介 水野 貴秀 坂井 真一郎 福島 洋介 齋藤 宏文

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.660, pp.25-31, 2009 (Released:2009-02-17)

参考文献数

7

被引用文献数

1 2

---

REIMEI/INDEX (INnovative-technology Demonstration EXperiment) is a 70kg class small satellite which the Institute of Space and Astronautical Science, Japan Exploration Agency, ISAS/JAXA, has developed for observation of auroral small-scale dynamics as well as demonstration of advanced satellite technologies. An important engineering mission of REIMEI is integrated satellite control using commercial RISC CPUs with a triple voting system in order to ensure fault-tolerance against radiation hazards. Software modules concerning every satellite function, such as attitude control, data handling, and mission applications, work cooperatively so that highly sophisticated satellite control can be performed. In this paper, after a concept of the integrated satellite control is introduced, the Integrated Controller Unit (ICU) is described in detail. Also unique topics in developing the integrated control system are shown.

著者

松野 隆 横内 滋 中村 佳朗

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.601, pp.80-86, 2004 (Released:2004-04-30)

参考文献数

15

被引用文献数

1 1

---

This paper describes the mechanism of the non-slender wing rock that occurs on a 45° delta wing, by focusing on its unsteady aerodynamic characteristics. In free-to-roll test the wing motions showed irregular oscillations the amplitude of which varied with time. In some cases, the wing suddenly changed its trajectory in the middle of the oscillation, and came to stop at roll angle φ=0°. The static rolling moment is quite nonlinear in characteristics, the profile of which has many critical states. The balance test for constant roll rate motion showed that the amount of time lag was not constant for roll angle, and that it is not linear for roll rate. The results of numerical simulation using the experimental data suggest that it is important to take into account the trajectory of the motion for a better understanding about the unsteady aerodynamic characteristics, associated with the non-slender wing rock.

著者

永田 靖典 石原 遼一 前田 真吾 河内 俊憲 柳瀬 眞一郎

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.67, no.1, pp.16-24, 2019 (Released:2019-02-05)

参考文献数

14

---

The electrodynamic heat shield is new type of heat protection system for atmospheric-entry vehicle, which utilizes the Lorentz force acting on the weakly ionized plasma flow inside the shock layer. A huge amount of calculation is necessary to estimate overall effect of the electrodynamic heat shield, because its effect interacts with the atmospheric-entry trajectory. In the present study, the Viscous Shock Layer (VSL) analysis method for electrodynamic heat shield is proposed for the quick analysis, which can calculate much faster than Navier-Stokes (NS) simulation. For this purpose, the VSL equations for the electrodynamic heat shield analysis are introduced under the ideal gas assumption, including circumferential momentum equation and Maxwell equations. The new method is also proposed to solve the new VSL equations. By the comparison to the NS simulation, the new VSL method gives good estimations of drag force and wall heat flux for wide ranges of interaction parameter and Hall parameter although the slight difference of wall heat flux at the stagnation point is observed. Therefore, the present VSL method could be applicable to the estimation tool of the electrodynamic heat shield effect.

著者

白木 邦明 片山 雅英 八坂 哲雄

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.49, no.572, pp.300-309, 2001 (Released:2002-04-26)

参考文献数

11

被引用文献数

3 3

---

Seven shaped-charge hypervelocity impact tests were conducted to evaluate the Japanese Experiment Module (JEM) space debris protection stuffed Whipple shield at an approximate velocity of 11 km/s. The shape and the characteristics of the shaped-charge jet differ from those of the light gas gun because of the jet generation mechanism. It is therefore necessary to evaluate and compensate the results for a solid aluminum sphere, which is the design requirement. Comparative two-dinensional hydrocode simulations were conducted to assess the shape effects on the impact damage. The shapes assessed are arrowheads that simulate the shaped-charge jet, hollow cylinders, and solid spheres. By assessing the projectile kinetic energy, the authors concluded that the shaped-charge jet produces three to five times more severe damage to the pressure wall than the solid sphere, even if both have the same mass. The authors also confirmed that the shaped-charge testing and hydrocode simulation correlate well for the pressure wall damage.

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

國中 均 西山 和孝 清水 幸夫 都木 恭一郎 川口 淳一郎 上杉 邦憲

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 = Journal of the Japan Society for Aeronautical and Space Sciences (ISSN:13446460)

巻号頁・発行日

vol.52, no.602, pp.129-134, 2004-03-05

被引用文献数

4 6

---

The microwave discharge ion engine generates plasmas of the main ion source as well as the neutralizer using 4GHz microwave without discharge electrodes and hollow cathodes, so that long life and durability against oxygen and air are expected. MUSES-C "HAYABUSA" spacecraft installing four microwave discharge ion engines was launched into deep space by M-V rocket on May 9, 2003. After vacuum exposure and several runs of baking for reduction of residual gas the ion engine system established the continuous acceleration of the spacecraft toward an asteroid. The Doppler shift measurement of the communication microwave revealed the performance of ion engines, which is 8mN thrust force for a single unit with 3,200sec specific impulse at 23mN/kW thrust power ratio. At the beginning of December 2003 the accumulated operational time exceeded 7,000 hours and units.

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, &ldquo;effervescent atomization&rdquo; 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.