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第54回流体力学講演会/第40回航空宇宙数値シミュレーション技術シンポジウム (2022年6月29日-7月1日. いわて県民情報交流センター(アイーナ)), 盛岡市, 岩手, The 54th Fluid Dynamics Conference / the 40th Aerospace Numerical Simulation Symposium (June 29 - July 1, 2022. Iwate Citizen Information Exchange Center (Aiina)), Morioka, Iwate, Japan, In this paper, the equivalent area distribution of a ten-seater supersonic forward-swept wing aircraft with canard was designed to obtain design knowledge toward the leading boom reduction. The equivalent area distribution of the aircraft was calculated by solving the compressible Euler equation, and a feasible target equivalent area distribution was generated based on Darden's method and compared with the equivalent area distribution. To acquire closer lift and geometry to the target, the main wing planform and the position of the main wing along the body axis and the vertical axis were modified, and the low boom performances were evaluated using the extended Burgers equation. The design results suggested that the forward-swept wing configuration with canard can divide the single peak of the leading boom into two peaks; thus, the sonic boom loudness of canard configuration was 2.5 PLdB lower than without-canard configuration., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA2230023013, レポート番号: JAXA-SP-22-007

第53回流体力学講演会/第39回航空宇宙数値シミュレーション技術シンポジウム (2021年6月30日-7月2日. 日本航空宇宙学会 : 宇宙航空研究開発機構(JAXA)オンライン会議), The 53rd Fluid Dynamics Conference / the 39th Aerospace Numerical Simulation Symposium (June 30 - July 2, 2021. The Japan Society for Aeronautical and Space Sciences : Japan Aerospace Exploration Agency (JAXA), Online meeting), In this paper, aerodynamic characteristics around the blade of the hexacopter ''HAMILTON (HexAcopter for Martian pIt crater exploraTiON)'' for Mars exploration are investigated to obtain design knowledge regarding multicopter drone flying in Martian atmosphere. Reynolds-averaged Navier-Stokes simulation with the moving overlapped grid was employed for aerodynamic evaluation of two cases; one is hexa-rotor case and the other is single rotor case in order to compare single rotor case and hexa-rotor case and reveal unique characteristics of multirotor case. According to computational results, in both cases, hexa-rotor and single rotor, the maximum figure of merit could be observed at higher hovering thrust conditions. It is suggested that the baseline blade geometry could generate thrust efficiently at higher thrust conditions. The flow structure around the hexa-rotor can be classified into three groups; turn-in side where the flow was drawn the inside by blades rotation, turn-out side where the flow was put out to the outside by blades rotation, and the center side which was located between the turn-in and turn-out sides. The rotors of the center side took the low figure of merit compared with the other rotors because of aerodynamic interference from the turn-in side and the turn-out side rotors. Therefore, the total figure of merit of all rotors increased when the distance among rotors is increased., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA2130027012, レポート番号: JAXA-SP-21-008

流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2020オンライン (2020年9月28日-30日. 日本航空宇宙学会 : 宇宙航空研究開発機構(JAXA)オンライン会議), Fluid Dynamics Conference / Aerospace Numerical Simulation Symposium 2020 Online (September 28-30, 2020. The Japan Society for Aeronautical and Space Sciences : Japan Aerospace Exploration Agency (JAXA), Online meeting), A conceptual study of Mars helicopter for the purpose of observation of the oval tunnels on the Mars has been carried out. Mainly from the limit of the storage size together with the Mars rover, a hexa-rotor drone is proposed with a gross weight of 3 kg. Each rotor consists of 4 blades while the rotor diameter is 460 mm. Optimized design of the airfoil to achieve higher hovering performance is being performed., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA2030013021, レポート番号: JAXA-SP-20-008

第50回流体力学講演会/第36回航空宇宙数値シミュレーション技術シンポジウム (2018年7月4日-6日. 宮崎市民プラザ), 宮崎市, 宮崎, 50th Fluid Dynamics Conference /the 36th Aerospace Numerical Simulation Symposium (July 4-6, 2018. Miyazaki Citizen's Plaza), Miyazaki, Japan, The study involved investigating the aerodynamic performance of several wings with different leading edge angles to validate the usefulness of a forward-swept wing in significantly reducing sonic boom at supersonic cruise. A total of 13 wing-body-engine nacelle configurations for supersonic business jet model were defined with varying wing planforms; the associated aerodynamic drag was evaluated using the three-dimensional compressive Euler equation, and the augmented Burgers equation was used to evaluate the acoustic level of the sonic boom. The calculated results for supersonic cruise conditions indicated that the maximum acoustic level of the sonic boom of a forward-swept wing was approximately 4.8 PLdB lower than that of the original backward-swept wing. Furthermore, a forward-swept wing reduced the aerodynamic drag as effectively as a backward-swept wing in supersonic cruise. The sonic boom signature on the ground level indicated that forward-sweeping of the wing led to multi-peaks signature on the bottom peak of the trailing sonic boom, and thus, the forward-swept wing could reduce the intensity of trailing sonic boom., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1830029020, レポート番号: JAXA-SP-18-005

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2017-04-28, 資料番号: PA1820022000

第48回流体力学講演会/第34回航空宇宙数値シミュレーション技術シンポジウム (2016年7月6日-8日. 金沢歌劇座), 金沢市, 石川, 48th Fluid Dynamics Conference /the 34th Aerospace Numerical Simulation Symposium (July 6-8, 2016. The Kanazawa Theatre), Kanazawa, Ishikawa, Japan, In this research, the supersonic wing design problem for SST with integrated engine intake and nacelle is discussed to obtain design knowledge of the supersonic airfoil in view of wing planform dependency in realistic configuration. Two planforms were considered ― a quadruple tapered wing with a high sweep-back angle and a single tapered wing with a low sweep-back angle. To reduce the computational time, the design problems were solved by a multi-fidelity design method, which is the evolutionary computation based exploration using the hybrid surrogate models based on two different physical fidelity results. The hybrid surrogate model which was combined Kriging model with radial basis function (RBF) makes optimizations more efficiently than Kriging model. To evaluate the aerodynamic performance, the compressive Euler equation and the linearized compressive potential equation were employed as two different fidelity solvers. Through optimum designs, two kinds of design knowledge are obtained. Firstly, in airfoil design, the shape of the forward camber and twisted angle have the largest effect on drag reduction. In case of low sweep-back wing, an airfoil which has small positive camber and small twisted down angle has found to be optimum. On the other hands, In case of low sweep-back wing, an airfoil which has a negative camber at the leading edge or higher twisted down angle compared to low swept-back wing’s one has shown to be optimum. Secondly, the way of aerodynamic interference between wing, engine, and fuselage depends on planforms., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1630031008, レポート番号: JAXA-SP-16-007

第47回流体力学講演会/第33回航空宇宙数値シミュレーション技術シンポジウム (2015年7月2日-3日. 東京大学生産技術研究所), 目黒区, 東京, 47th Fluid Dynamics Conference /the 33rd Aerospace Numerical Simulation Symposium (July 2-3, 2015. Institute of Industrial Science , the University of Tokyo), Meguro-ku, Tokyo, Japan, In wing design, as wing planforms strongly depend on the sectional airfoil design, it is obvious that optimum airfoil will be different if multipoint aerodynamic performance of wing planform differs. Thus, this paper consists of two parts. In the first part, to obtain quantitative knowledge of multi-point supersonic aerodynamic performance of various wing planforms, the liner theory is investigated using the computational fluid dynamics (CFD). For a given supersonic cruise speed, when the leading edge of the wing becomes the subsonic edge, our theoretical study says the higher swept-back wing has the lower zero-lift drag. On the other hand, when the leading edge of the wing becomes supersonic edge, the lower swept-back wing has the lower zero-lift drag. This result suggests the having a lower swept-back wing will be a reasonable choice for the aircraft which flies at a certain supersonic speed. Secondly, multi-point designs of the supersonic wing using efficient global optimization (EGO) were considered for two kinds of planform; one is cranked arrow wing which has high sweep-back leading edge, another is taper wing which has sweep-back leading edge. According to the analysis of design results, different optimum airfoil geometries are obtained between each planform and it is also shown that the shape of the camber line of airfoil plays an important role for both the planforms in order to reduce wave drag in supersonic cruise., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1630005021, レポート番号: JAXA-SP-15-013