著者

佐藤 昌之 村岡 浩治 穂積 弘毅 眞田 幸尚 山田 勉 鳥居 建男

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.65, no.2, pp.54-63, 2017 (Released:2017-04-05)

参考文献数

10

被引用文献数

1 1

---

This paper is concerned with the design problem of preview altitude controller for Unmanned Airplane for Radiation Monitoring System\nobreakspace {}(UARMS) to improve its control performance. UARMS has been developed for radiation monitoring around Fukushima Dai-ichi nuclear power plant which spread radiation contaminant due to the huge tsunamis caused by the Great East Japan Earthquake. The monitoring area contains flat as well as mountain areas. The basic flight controller has been confirmed to have satisfactory performance with respect to altitude holding; however, the control performance for variable altitude commands is not sufficient for practical use in mountain areas. We therefore design preview altitude controller with only proportional gains by considering the practicality and the strong requirement of safety for UARMS. Control performance of the designed preview controller was evaluated by flight tests conducted around Fukushima Sky Park.

著者

平野 正隆 宮路 幸二

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.611, pp.535-540, 2004 (Released:2005-02-25)

参考文献数

8

被引用文献数

1 1

---

A wing rock is known to be a self-excited rolling oscillation of a delta wing that is induced by unsteady aerodynamic forces. In this study, free-to-roll simulations are carried out by incorporating time-accurate computational fluid dynamics with an equation of motion of a wing. A limit cycle oscillation and the histogram of a hysteresis in the rolling moment, which has four peaks within one cycle, are successfully simulated. The strength of the leading-edge vortices at a fixed roll angle is rather different from that during the wing rock especially at large angular velocities and that causes the characteristics behavior of the unsteady moments.

著者

岡林 希依 末永 宇識 淺井 雅人

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.64, no.1, pp.41-49, 2016 (Released:2016-02-05)

参考文献数

28

被引用文献数

2

---

For practical CFD-aided design of riblets on aircrafts, we are aiming to develop a Reynolds-Averaged Navier-Stokes (RANS) turbulence model which can simulate drag reduction effects without resolving fine-scale flows near the riblets. Wilcox's rough wall boundary condition for Menter's SST model is modified to reproduce velocity shift in logarithmic region corresponding to riblet's drag reduction effects. Two basic relations for this model are derived from available experimental data and parametric analysis, and are validated in zero-pressure gradient boundary layers with two different-geometry riblets. Drag reduction rates corresponding to experimental results can be obtained with these relations. The new model, however, underestimates the effects of riblet mounted on NACA0012, which suggests that further improvement of the model is needed to account for influences of pressure gradient.

著者

溝口 誠 山口 裕

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.60, no.3, pp.121-127, 2012 (Released:2012-10-23)

参考文献数

15

被引用文献数

2 3

---

The effect of aspect ratio (AR) on the aerodynamic characteristics of rectangular wings is investigated. Reynolds numbers considered are 7.6×104 and 5.2×104. Experimental results are compared with analytical ones obtained from Lamar's method. It is shown that the aspect ratio of wings affects the stall characteristics when AR≤2.0. The aspect ratio also has an effect on the lift slope if AR≤1.5. Furthermore, maximum lift coefficients increase when AR≤1.0. Comparisons show that the variations of aerodynamic characteristics are caused by tip vortices. It is also considered that the position of the center of pressure is varied with the angle of attack because of the effects of the laminar separation bubble and tip vortices on wing surfaces.

著者

榊 和樹 舩橋 友和 中谷 辰爾 津江 光洋 金井 竜一朗 鈴木 恭兵 稲川 貴大 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.65, no.5, pp.193-199, 2017

---

The longitudinal combustion instability characteristics of a pintle-type injector for a bipropellant rocket engine combustor are investigated experimentally. An optically accessible combustion chamber are used to observe unsteady combustion behaviors under oscillating combustion conditions. CH* chemiluminescence and backlit spray images are observed simultaneously with two high-speed cameras. Two experiments with the propellant total momentum ratio (TMR) of 0.76 and 2.48 are conducted, whereas the combustion pressure and the propellant mixture ratio are 0.45 and 1.6, respectively. The combustion oscillations at the natural frequencies of the chamber longitudinal acoustic mode are observed when the TMR is 0.76. The combustion oscillation is caused by the coupling between the heat release and the combustion chamber acoustics. When the TMR is 2.48, the combustion oscillations at the frequencies of 400 and 800Hz, which are lower than the first longitudinal mode frequency, are observed. Since the 400Hz corresponds to the convective time scale in the combustion chamber, the oscillations could be caused by one of the convective modes such as entropy wave.

著者

角銅 洋実 榊 和樹 中谷 辰爾 津江 光洋 金井 竜一郎 稲川 貴大 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.65, no.1, pp.1-9, 2017

---

The pintle injector is a promising candidate for injection systems of future rocket engines because of the throttling capability, the combustion stability, and the low manufacturing cost. Few studies focusing on fundamental aspects of a pintle injector have been conducted, and most of the design parameters of a pintle injector is determined mainly based on the empirical knowledge. Among the design parameters, total momentum ratio (TMR) is one of the most important parameters since spray structure is dominated by TMR. Therefore, combustion experiments using an ethanol/liquid oxygen rocket engine combustor with a planar pintle-type injector which is designed for optical measurements for a pintle injector are conducted at combustion pressure (<I>P_c</I>) = 0.37-0.42MPa, mixture ratio (O/F) = 1.31-1.49, TMR = 0.32-3.65 to investigate the effects of propellant momentum ratio on the combustion behavior. The spray structure under hot fire conditions is observed using high-speed imaging techniques with a backlit configuration. In the oxidizer-centered configuration, the characteristic exhaust velocity efficiency (<I>η<SUB>C</SUB><SUP>*</SUP></I>) decreases with the increase of the TMR. The atomized propellant impinge on the combustor wall before the vaporization and reaction at higher TMR. In the fuel-centered configuration, though the propellant spray is more inclined to the direction of the upper combustor wall at higher TMR, the <I>η<SUB>C</SUB><SUP>*</SUP></I> does not change with the TMR. In both oxidizer-centered and fuel-centered, higher <I>η<SUB>C</SUB><SUP>*</SUP></I> is provided in the condition of higher injection pressure drop.

著者

原田 正志

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.66, no.3, pp.75-83, 2018 (Released:2018-06-05)

参考文献数

10

---

In this paper, a design method to obtain the maximum static thrust ducted fan is proposed. In this method, the shape of the optimum blade is obtained by minimizing the objective function. The objective function includes the effect of the leading edge suction that acts on the duct's rip. The shape of the optimum blade is tapered, however, a small expansion is confirmed at blade tip. The amount of this expansion depends on the radius of duct's rip. From the optimized ducted fan, it is concluded that the duct generates nearly half of the total thrust, which is also predicted by the simple momentum theory.

著者

五井 龍彦 田中 裕久 中島 健一 渡辺 浩二

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.678, pp.203-209, 2010 (Released:2010-07-26)

参考文献数

6

被引用文献数

4 3

---

A half-toroidal traction drive CVT has a feature of small spin at traction pitch in whole speed ratio range of 1:4, which suits to transmit high rotational speed with minimum temperature increase of traction surface. Research activity on traction drive CVT has commenced in 1996 for applying it to an aircraft 24,000rpm constant-speed generator instead of a hydro-static transmission. This paper shows fundamental design of 90kW traction drive integrated drive generator, ``T-IDG", and stability analysis on a sensor-less electro-hydraulic speed control servo-mechanism by bond graphs. The performance test of T-IDG mounted on a test bench and an actual jet engine proved that the control system using sensor-less servomechanism can keep the generator speed within MIL-STD-704E allowable limit against steep changes of speed and load.

著者

永田 靖典 山田 和彦 鈴木 宏二郎 今村 宰

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.1-8, 2019 (Released:2019-02-05)

参考文献数

13

被引用文献数

1

---

The satellite communication system without ground antennas is highly beneficial to ease construction and maintenance of the ground station. To realize it, the Iridium communication service which is consisted of 66 satellites on the LEO (Low-Earth Orbit) is focused. The telemeter and command data are transmitted and received through the Internet, Iridium ground station, and Iridium satellites. Then, only a PC connecting to the Internet is required for the present telecommunication system. To demonstrate this concept, the EGG (re-Entry satellite with Gossamer aeroshell and GPS/iridium) nanosatellite mission was conducted in 2017, which is the first satellite operated via only the Iridium SBD (Short Burst Data) communication. In this paper, the communication performance of the Iridium communication applied to LEO satellite is investigated and the EGG mission result is described. Trajectory-based simulation shows that the present system will function well even under the Doppler shift criteria, though the available time rate will be degraded. Actually, it worked successfully on the EGG mission regardless of the satellite location. Moreover, the telemeter data was acquired in semi-real time manner on the atmospheric-entry phase, which is very difficult for the ordinary ground antenna system. This should be the important feature of the present system.

著者

西川 雅章 逸見 啓 パク サンチョル 灘部 岳晃 武田 展雄

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.58, no.680, pp.261-268, 2010 (Released:2010-09-27)

参考文献数

15

被引用文献数

1 1

---

Carbon fiber-reinforced composites have been recently applied for engine fan blades, because of their high specific strength. In the design of the fan blade, the bird-strike impact is one of the greatest concerns, since impact-induced damage can lead to the engine stall. This study presented a numerical method to analyze the bird-strike impact as a soft-body impact on cantilevered composite panel. Especially, we coupled a stabilized dynamic contact analysis, which enables predicting impact force on the panel appropriately, with laminate damage analysis to predict the impact-induced progressive damage in the composite. This method was verified through the comparison with the experimental results. With the numerical method, we investigated the effect of impact condition, blade thickness and shape on the impact-induced damage in composite fan blade subjected to a bird strike. An intermediate blade thickness and a large blade curvature help improving the bird-striking impact resistance of the composite.

著者

歌島 昌由 川口 淳一郎

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.50, no.580, pp.210, 2002 (Released:2003-09-02)

参考文献数

3

被引用文献数

1 2

---

The stability of the orbits around the sphere of influence of the secondary body in the circular restricted three-body problem is discussed. This orbit is called “Pseudo Orbit” here. Though there exists a stability limit for the inclination of the pseudo orbit, the whole story of the instability was not resolved. In this paper, it is shown at first that the out-of-plane motion of the pseudo orbit causes disturbances in the in-plane motion by the method of virtual energy. Then, it is shown that the disturbances are governed by the Mathieu’s equation which has the periodic coefficient, and the rigorous mathematical property of the instability of the pseudo orbit is presented.

著者

畑井 啓吾 池田 博英

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.5, pp.174-180, 2019 (Released:2019-10-05)

参考文献数

32

---

The suitable fuel for reduced-toxicity hypergolic bipropellant has been explored in this study. High concentration of hydrogen peroxide and sodium borohydride were used as an oxidizer and a fuel additive for ignition source. Fuel candidates were narrowed down by many requirements such as toxicity, chemical regulation, storability, cost, specific impulse, solubility of additive and ignition delay. As a result, 3-methylaminopropylamine (MAPA) was selected as the best fuel for reduced-toxicity bipropellant. MAPA doped with sodium borohydride showed very fast hypergolicity with hydrogen peroxide and its ignition delay time was less than 10msec. MAPA and hydrogen peroxide bipropellant can achieve 98.3% of theoretical specific impulse of MMH/NTO, whereas MAPA has low toxicity compared with MMH.

著者

河内 俊憲 三谷 徹 平岩 徹夫 富岡 定毅 升谷 五郎

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.51, no.595, pp.403-411, 2003 (Released:2003-09-26)

参考文献数

15

被引用文献数

2 6

---

A one-dimensional theoretical method for an evaluation of the net thrust of a scramjet engine is presented. To calculate the thrust performance of the engine analytically, an efficiency characterizing compression process, such as recovery factor in total pressure or kinetic energy efficiency etc., is necessary. In the previous theoretical method, this efficiency was roughly assumed. Although the effect of aerodynamic parameters and configuration parameters on the thrust can be investigated with this rough assumption, the net thrust evaluated with this method was not enough accurate to be compared with the measured thrust in experiments. The total pressure loss is chosen as the efficiency in this paper. This total pressure loss is evaluated from the engine internal drag with the wind tunnel experiment, which is due to irreversible process through the engines. The theoretical maximum thrust of the engines can be calculated with this new method.

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

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.