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SST-CFDワークショップ.次世代超音速機の数値シミュレーション利用技術に関する国際ワークショップ 航空宇宙技術研究所 20011203-20011205 東京 日本, SST-CFD Workshop. International Workshops on Numerical Simulation Technology for Design of Next Generation Supersonic Civil Transport National Aerospace Laboratory 20011203-20011205 Tokyo Japan, This paper provides CFD (Computational Fluid Dynamics) flow analysis results of the NAL NEXST-1 (National EXperimental Supersonic Transport-1) for the 3rd NAL SST (SuperSonic Transport) CFD workshop. A hybrid unstructured grid system was employed for viscous aerodynamic analysis. Computations were conducted for both wind tunnel test condition and Flight Test condition. The CFD results showed very good correlation with wind tunnel test results., 資料番号: AA0063609059, レポート番号: JAXA-SP-06-029E

SST-CFDワークショップ.次世代超音速機の数値シミュレーション利用技術に関する国際ワークショップ: Toward the Future form NEXST-1 Flight Trial 宇宙航空研究開発機構 20061012-20061013 東京 日本, SST-CFD Workshop. International Workshops on Numerical Simulation Technology for Design of Next Generation Supersonic Civil Transport: Toward the Future form NEXST-1 Flight Trial Japan Aerospace Exploration Agency 20061012-20061013 Tokyo Japan, Software for aerospace vehicle surfaces is applied and further developed as a Parameterized Geometry Preprocessor suitable for aerodynamic design and optimization. Airfoil families are designed with knowledge based parameters and their variations are used for optimization strategies, as well as with spanwise parameter variations to shape arbitrary lifting wings. Integration with fuselage results in a one-block surface grid for wing-body configurations which is found practical for rapid prototype design. Generation of scalar distributions along surface gives target pressure functions to support the input of inverse design codes. Case studies derived from the NEXST (National EXperimental Supersonic Transport) supersonic transport project and other concepts illustrate the value of this approach., 資料番号: AA0063609069, レポート番号: JAXA-SP-06-029E

航空宇宙技術研究所 17-19 Jan. 2000 東京 日本, National Aerospace Laboratory 17-19 Jan. 2000 Tokyo Japan, 超音速輸送機に対するNALの実験(NEXST(小型超音速実験機計画)-1)の第1段階において、超音速航行時での抵抗軽減のための空力設計に焦点が当てられた。CFD(計算流体力学)が、この研究には大変有益であると考えられた。設計段階で4つの空力概念が適用された。(1)矢羽根平面型、(2)ねじれ翼、(3)面積則胴体、(4)自然層流(NLF)翼である。NLFの概念は摩擦抵抗低減のために考案された。NLFは今までSSTに適用されたことはなく、このプロジェクト独自の試みである。NLFを実現するために、先ず、超音速航行速度での翼面上圧力分布を設計し、超音速微小擾乱方程式にもとづく逆設計手法を適用した。10回以内の繰り返し計算で、目標の圧力分布を得ることに成功した。また、遷移点は非圧縮性および圧縮性境界層遷移点予測の計算機コードを用いて予測し、良い結果を得た。以上のことから、CFDは解析の手法としてのみならず設計の手法として用いることができることが分かった。NEXST-1の詳細設計は1999年中に終了した。次のCFD設計の目標はNEXST-2であり、現在、基本設計段階にある。, At the first stage of NAL's experiment for supersonic transport (NEXST (National Experimental Supersonic Transport)-1) project, the aerodynamic design focused on reducing the drag at the supersonic cruising. The CFD (Computational Fluid Dynamics) was supposed to be a powerful tool for the study. Four main aerodynamic concepts were applied in the process of designing; (1) arrow type planform, (2) warped wing, (3) area-ruled fuselage, and (4) wings with a Natural Laminar Flow (NLF). The NLF concept was devised for the friction drag. It has never been applied to SST up to now, which is one of original idea for this project. To realize the NLF on the wing at the supersonic cruising, firstly a pressure distribution on wing surfaces at supersonic cruising speed was designed and secondly an inverse design method based on the supersonic small perturbation equation was applied. After less than ten iterations, the target pressure distributions were obtained. Then the transition positions were estimated successfully by the CFD code of the incompressible and compressible boundary layer transition prediction. It must be noted that the CFD code was useful not only as an analytical tool but also as a method for the designing. The critical design of NEXST-1 has been completed in 1999. The next target of CFD based design is NEXST-2, which is now on the preliminary design phase., 資料番号: AA0028638010, レポート番号: NAL SP-49T

航空宇宙技術研究所 17-19 Jan. 2000 東京 日本, National Aerospace Laboratory 17-19 Jan. 2000 Tokyo Japan, NALの最初のSSTモデルに用いる翼の空力形状が、超音速逆設計法を用いて設計された。この手法は翼・胴体形状を取り扱い、各スパン位置での翼断面幾何形状を提供する。設計目標は、マッハ2の速度でのNLF(自然層流)翼の実現である。逆設計手法の最初の系を、いくつかの設計制約を満足するように修正しなければならい。この方法により、従来の設計法で設計したものよりずっと望ましい特性を持つように翼断面形状を設計した。NLF翼を実現する空力学については、修正した方法は良く機能する。設計翼の圧力分布は、目標圧力と良く一致した。制約については、その多くが修正した設計法を用いることで満たすことができる。しかし、厚さ制約制御の過程で困難さを見出した。圧力制約に対処する将来計画を論じた。, Aerodynamic shape of a wing for NAL (National Aerospace Laboratory)'s first SST model has been designed by a supersonic inverse design method. This method handles wing-fuselage configurations and provides wing section's geometry at every span for Navier-Stokes flowfields. The design target is an NLF (Natural Laminar Flow) wing at the speed of M(sub infinity) = 2.0. The original system of the inverse design method has to be modified so that several design constraints can be satisfied. By means of the method, a wing section shape has been designed to have much more desirable characteristics than that by the traditional design method. In terms of aerodynamics to realize an NLF wing, the modified method works very well. The pressure distribution of the designed wing shows good agreement with the target pressure. In terms of constraints, most of them can be satisfied in the modified design method; however, difficulty has been found during the process for thickness constraint control. The prospective strategy to cope with the thickness constraint is discussed., 資料番号: AA0028638012, レポート番号: NAL SP-49T

SST-CFD Workshop. International CFD Workshops for Super-sonic Transport Design 航空宇宙技術研究所 19980316-19980317 東京 日本, SST-CFD Workshop. International CFD Workshops for Super-sonic Transport Design National Aerospace Laboratory 19980316-19980317 Tokyo Japan, A numerical optimization code for the aerodynamic design of wing-body configurations has been recently developed at ONERA. This optimization code has been built by coupling the CONMIN (CONstrained MINimization) code of G.N. Vanderplaats which performs the constrained minimization of a function of N variables with as ONERA Euler code for aerodynamic computations. For this purpose, a geometry generator taking into account a great number of design variables and an automatic grid generator have also been developed. In the first part of this paper, the general organization of the ONERA optimization code is presented. In a second part, the first results from an application of this code to the design of a supersonic transport aircraft are presented and the strategy of optimization is discussed., 資料番号: AA0063609014, レポート番号: JAXA-SP-06-029E

SST-CFDワークショップ.次世代超音速機の数値シミュレーション利用技術に関する国際ワークショップ 航空宇宙技術研究所 20011203-20011205 東京 日本, SST-CFD Workshop. International Workshops on Numerical Simulation Technology for Design of Next Generation Supersonic Civil Transport National Aerospace Laboratory 20011203-20011205 Tokyo Japan, In this research, multiobjective optimization system has been developed to reduce the aerodynamic drag and the sonic boom for SST (SuperSonic Transport) wing-body configuration. Wing and fuselage are defined by 131 design variables and optimized at the same time. Structured multiblock grids around SST wing-body configuration are generated automatically and an Euler solver is used to evaluate the aerodynamic performance of SST wing-body configuration., 資料番号: AA0063609056, レポート番号: JAXA-SP-06-029E

航空宇宙技術研究所 17-19 Jan. 2000 東京 日本, National Aerospace Laboratory 17-19 Jan. 2000 Tokyo Japan, 機体とエンジンナセルの統合化を考慮して、マッハ2.0で飛行する縮尺超音速実験機の数値シミュレーションを行った。重合格子法を含む3次元オイラーCFD(計算流体力学)コードを用いて、複雑な飛行機形状周りの流れ場を解いた。計算して得た圧力分布は、風洞実験で得られた結果とよい一致を示した。さらに、CFDコードと抗力を最小にする最適化の手法を組み合わせ、空力設計ツールを開発した。まず軸対称物体に適用し、本方法を検証した。得られた最適化機体形状はSears-Haackの機体とよく一致している。次に、翼と胴体からなる2つの物体に適用した。最適な機体形状での圧力抵抗は、Sears-Haackの結果よりおよそ9%小さく、最終的な体積は始めの体積に維持されていた。, The numerical simulation of a Mach 2.0 scaled supersonic experimental airplane is conducted with the consideration of the integration between air-frame and engine nacelles. A three-dimensional Euler CFD (Computational Fluid Dynamics) code with an overset-grids technique is adopted for solving the flow-field around a complex airplane configuration. The calculated pressure distributions were compared with wind tunnel test data and showed good agreement with them. The aerodynamic design tool, which combines the CFD code with an optimization technique for drag minimization, was developed. At first, it is applied to an axisymmetrical body in order to validate this design tool. The result showed that the optimized body geometry agrees well with the Sears-Haack body. Next, it was applied to two bodies under a wing-body configuration. The pressure drag of the optimized configurations was about 9 percent lower than that of the Sears-Haack body and their final volumes were maintained at the initial volume., 資料番号: AA0028638015, レポート番号: NAL SP-49T

物体後流内部の物理量を積分して抵抗と揚力を算出する手法(Wake Integral Method)を3次元CFD(Computational Fluid Dynamics)データに適用し、飛行機の各要素が抵抗全体に及ぼす影響の度合いの定量的な評価を行った。この手法では抵抗を発生要因によってProfile DragとInduced Dragに分解し、さらに空気力の定量的な分布を得ることができる。従って、CFDにおいても風洞試験データにおいても同様に抵抗発生要因を特定し、設計にフィードバックすることが期待できる。本研究ではNACA0012断面を有する矩形翼と翼胴形態であるDLR F6模型に対する解析を行い、解析結果から得られる知見について考察を行った。, The wake integral method, a method that analyzes aerodynamic forces by integral in the wake of a model, was applied to three-dimensional CFD (Computational Fluid Dynamics) data and a quantitative assessment of aerodynamic forces produced by airplane elements was performed. The method allows the drag force exerted on a body to be decomposed into profile and induced drag components, and provides their distributions. By using this method, a designer can expect to obtain insight into aerodynamic drag production factors from CFD data and wind tunnel wake traverse data. In this study, CFD spatial data of a rectangular NACA0012 section wing and the DLR F6 wing-body model were analyzed and the insights gained into the aerodynamic force distributions and drag were examined., 資料番号: AA0063909000, レポート番号: JAXA-RR-07-030E

SST-CFDワークショップ.次世代超音速機の数値シミュレーション利用技術に関する国際ワークショップ 航空宇宙技術研究所 20011203-20011205 東京 日本, SST-CFD Workshop. International Workshops on Numerical Simulation Technology for Design of Next Generation Supersonic Civil Transport National Aerospace Laboratory 20011203-20011205 Tokyo Japan, An implicit multiblock Navier-Stokes solver, which contains the LU-SGS (Lower-Upper Symmetric Gauss-Seidel) subiteration method and the HLLEW (Harten-Lax-van Leer Einfeldt-Wada) scheme, has been developed for numerical simulations on complex and realistic aerodynamic configurations. One-level halo cells are used to communicate data between abutting blocks. The resulting method is applied to the NAL SuperSonic Transport (SST) model., 資料番号: AA0063609061, レポート番号: JAXA-SP-06-029E