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JAXA Special Publication, 宇宙航空研究開発機構特別資料

This paper presents numerical study on the 2-D high lift devices (HLD). CFD analyses of 2 element (NLR-7301) and 4 element (Boeing Model C) airfoils was conducted, using 2 different CFD codes (JAXA UPACS and MHI in-house codes). MHI in-house code adopts overset grid method. A new method of overset pattern optimization was developed, and grid dependency due to interpolation process is reduced by this method. The detail process of the method is described. Through the validation study, both CFD results agree well with WTT results. However, through the careful investigation of the CFD results, it was found that turbulence transition treatment of CFD highly affected the estimation of HLD aerodynamic characteristics. Finally, it comes to the conclusion that accurate prediction of the transition location is necessary for that of aerodynamic characteristics of HLD., JAXA Special Publication, 宇宙航空研究開発機構特別資料

JAXA Special Publication, 宇宙航空研究開発機構特別資料

A supersonic jet into complex geometry and its accompanying acoustic field have been investigated by using Euler Equation/Linearized Euler Equation (LEE) hybrid methodology here. As a first step, we have examined its performance by computing traveling sinusoidal waves. Then, we found that the hybrid methodology achieves higher accuracy than the Euler computation when combined with a fifth-order WENO (Weighted Essentially Non-Oscillatory) scheme. Based on this knowledge, we have conducted both of fully third-order Euler/LEE and third-order-Euler/fifth-order-LEE hybrid computations. According to the results, the computed acoustic field is mainly composed of three waves having distinct frequencies: a high frequency wave (0.5 Hz) which seems to be caused by interferences from the wall, a medium frequency wave (2.2 Hz) corresponding to first-mode eigenfrequency of the jet exit geometry, and a low frequency wave (10 Hz). The computed pressure values are rather different between the two results, although these frequencies are not so much. This fact implies that the more we extend the region of fifth-order computation, the more the computed pressure values approach to physically correct ones in quantitative view., JAXA Special Publication, 宇宙航空研究開発機構特別資料

According to the recent rapid progress of high performance computing and numerical algorithm, a CFD-based aerodynamic design methodology is becoming an important tool with wind tunnel testing. The 3rd Research Center, TRDI-JDA has implemented the development and performance tests a CFD-based design system CASPER (Computational Aerodynamics System for Performance Evaluation and Research), with major domestic aircraft manufactures until March 2001. In this paper, mainly shown is part of aerodynamic and aeroelastic computed results obtained in performance tests. Actually, for the code validation, various types of aircraft and airfoil configurations are computed using the CASPER and compared well to wind tunnel testing data and other computed results. In addition, as an example of CFD multidisciplinary simulation providing the CFD data obtained in its aerodynamic characteristic module, the aeroelastic simulation can be normally performed. The CASPER can be expected to be powerful tool for conceptual and basic design stage of advanced aircraft at the next generation., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料

This paper presents rotor aerodynamic analysis including influence of a fuselage using an unsteady Euler code. A moving overlapped grid method is applied in the code and four types of grid, inner and outer background grids, blade grid, and fuselage grid are used to accurately simulate the rotor-fuselage interaction. As a result, the effect of the fuselage on rotor aerodynamics is captured in hover and low-speed forward flight conditions by comparing the blade surface pressure with and without the fuselage., JAXA Special Publication, 宇宙航空研究開発機構特別資料

In this paper, the numerical simulation method for the supersonic intake performance is proposed. According to the wind tunnel test by NAL, the performance of the supersonic intake integrated to a wing-body was different from the nacelle-only configuration. This result suggested that the intake performance is affected by the wing-body existence. To inspect this difference, the simulations with the nacelle-only configuration and wing-body-nacelle configuration were performed and the calculative results were compared. To obtain higher numerical accuracy of the shock wave, the structured Navier-Stokes code with the low-Reynolds number kappa-epsilon turbulent model were applied to inside the nacelle, while to adapt to the complex geometry of the wing-body-nacelle configuration, the unstructured Euler code was applied to outside the aircraft model. To perform this calculation, the structured-unstructured zonal approach was developed., JAXA Special Publication, 宇宙航空研究開発機構特別資料

The importance of accurate and fast interpolation algorithm is growing up for multi-body configuration with arbitrary overlap. One of the critical cases can be a helicopter simulation because of the complex relative movement of rotor-rotation and body motion. In this paper, new searching algorithms are implemented for the interpolation between two different grids, Cartesian grid and curvilinear grid, of which the overlapped grid system consists for the massive computation of the full helicopter configuration. These searching algorithms are proposed to make full use of (1) the characteristics of Cartesian grid, (2) special geometric configuration of helicopter, and (3) load balancing in parallel computation. In the first stage, Alternating Index Searching (AIS) algorithm, which alternates a searching direction by jumping the grid index to the searching point, is constructed to compare the iteration speed with a conventional Linear Searching (LS) algorithm. Simple two dimensional problems and three dimensional helicopter simulations are conducted to compare the efficiency of these searching algorithms. The result shows a considerable enhancement in computing time for whole computation domain. In the second stage, Reverse Index Searching (RIS) algorithm, which is developed to consider the load balance among each Processing Element (PE) during parallel computation, is proposed. By applying these searching algorithms, efficient massive computation can be achieved for the helicopter configuration., ロータの回転や6自由度の機体運動などの複雑な動きのため、メイン／テールロータおよび胴体からなるヘリコプタの数値シミュレーションにおいて、正確で速い補間アルゴリズムの重要性が高まってきている。本報告では、直交格子と曲線格子で構成される移動重合格子を利用したCFD(Computational Fluid Dynamics)コードに対して、より正確で早い補間法を提案した。新しい補間法では、(1)直交格子の特性、(2)ヘリコプタ・ブレードの特殊な幾何学的配置、および(3)並列計算時の計算負荷バランスなどを十分有効に利用できるアルゴリズムが考案されている。第1章では、Alternating Index Searching(AIS)アルゴリズムを提案し、従来のLinear Searchingアルゴリズムに対し、2次元の簡単なケースと実際のヘリコプタを模擬した3次元計算のケースで補間計算の速度を比べた。第2章では、並列計算における各計算ノードの負荷バランスを考慮したReverse Index Searching(RIS)アルゴリズムを提案した。この補間法を利用することによって、ヘリコプタのより効果的な大型計算を実現することができた。, JAXA Research and Development Report, 宇宙航空研究開発機構研究開発報告

In the present study, a small magnetic sail consisting of a 4 m-diameter coil, which seems to be reasonable size as a test vehicle realizable within the present technology level, is considered. Interaction of the solar wind with the magnetic sail is numerically simulated by the full particle (PIC) method. Fundamental features of the flow field and the induced electromagnetic field around the small magnetic sail are clarified. Force acting upon the magnetic sail, which is estimated by considering the Lorentz force generated by the induced electromagnetic field and the momentum change of the solar wind around the magnetic sail, is in the order of 10(exp -3) mN. Additionally, optional concepts of sailing propulsion, which use applied electric field or artificial charged particles, are also considered. The new concepts may improve the acceleration performance and/or payload capacity of the sailing propulsions., コイル直径4mの磁気セイルについて、Full PIC法を用いて太陽風と電磁場の干渉解析を行い、太陽風流れ場や誘導電磁場の基本的な特性について調べるとともに、太陽風粒子の総運動量変化やJ×B力から磁気セイルの推力を見積もった。その結果、ここで想定したような磁気セイルでは10(exp -3)mN程度の推力が得られることが分かった。また、セイリング推進の性能を向上させるオプションとして、磁場ではなく電場を印加した場合の効果や、電荷を帯びた微粒子で構成される光圧を利用した新しい推進システムの可能性について検討した。, JAXA Research and Development Report, 宇宙航空研究開発機構研究開発報告

In this paper the SUMMAC Method for solving time dependent viscous incompressible flow of fluid with free surface was investigated. Designed was a computer program known as 'type-A' to reproduce exactly the features of the SUMMAC Method. A technique for extrapolation of flow velocity components out into vacant space and a method for determining free surface are also described here in detail. Four items were proposed to improve the numerical stability of the original method. An improved version 'type-B' was designed to integrate these four items of the computer program. Both computer programs were tested on the 'Impinging Jet' example. Starting from accurate initial values, the behavior of time advancing solutions was compared and discussed here. The improved version 'type B' proved superior to 'type-A', and the so-called Hirt's 'General Corrective Procedure' used to ascertain its effectiveness. The relationship between the lattice interval delta-x and time increment delta-t is also discussed here. A trial analysis for a viscous flow example was performed successfully., 自由表面を有する非圧縮粘性流体の非定常流れを解くSUMMAC法について調べた。同法を忠実に反映する流れ解析プログラムを作成した。これをA型と呼ぶ。速度成分を流れの外部の空間へ外挿する方法と自由表面を決定する方法を詳述した。同法の数値解法上の安定性を改善するために4項目を提案し、これらを組み込んだB型と呼ぶプログラムを作成した。両プログラムを「噴流衝突」問題に適用して試験を行った。試験は非粘性定常流れについて正確な初期値を与えて時間進行する解を比較する方法でおこなった。B型はA型より優れていることが判明した。Hirtが提唱した「一般的修正手順」が有効であることをたしかめ、格子間隔と時間きざみの関係を論じた。粘性流についての計算例では良好と見える結果を得た。, Technical Report of National Aerospace Laboratory, 航空宇宙技術研究所報告

High-Speed Impulsive (HSI) noise generated by helicopter rotors in hover or in forward flight is computed using two Euler/Kirchhoff codes, separately developed by NAL and ONERA as part of the cooperative research project between the two institutes. The project is entitled 'Rotorcraft Euler Flow Simulation' and its main purpose is to validate the Euler/Kirchhoff codes in non-lifting delocalized test cases. The pressure distributions on the blade surface computed by the Euler codes are compared before the analysis of aeroacoustic results provided by both Kirchhoff codes. In hover the computations are conducted using three types of grids: coarse, medium, and fine. The aerodynamic computations were compared and they are in reasonable agreement each other. The acoustic results obtained by each partner agree well with an experiment conducted by Boxwell et al. In forward flight, the aerodynamic codes provide similar results on the blade surface, with a satisfactory correlation with the experiment. However, some discrepancies appear in the acoustic results., 航空宇宙技術研究所(NAL)とフランス航空宇宙研究所(ONERA)との共同研究の一環として、双方で独自に開発されたオイラー/キルヒホッフ法のコードを用いて、ホバリングおよび前進飛行時にヘリコプタから発生する高速衝撃騒音を計算し、結果を比較した。この共同研究は「オイラーコードによる回転翼機の流れ場シミュレーション」と題されており、その主な目的は、無揚力で非局所化現象の起こるケースにおいて両者のオイラー/キルヒホッフ法コードを検証することにある。比較は、オイラーコードによる空力計算の結果(ブレード翼面上の圧力分布)とキルヒホッフコードによる音響計算の結果(騒音の音圧波形)で行った。ホパリングのケースでは、3種類の格子(粗い密度の格子、中程度の密度の格子、細かい密度の格子)で計算を行い、空力計算、音響計算ともに両者の結果は良く一致した。さらに、音圧波形は双方ともBoxwellらの実験結果とも良く一致した。また、前進飛行のケースでは、ブレード翼面上の圧力分布は実験結果を十分満足に予測するとともに、お互いまずまずの一致を見せたものの、音圧波形ではいくつかの相違点が見出された。, Technical Report of National Aerospace Laboratory, 航空宇宙技術研究所報告

The unsteady flow phenomenon in turbomachinery changes drastically with changing operating condition. It is important that the various flow phenomena are predicted accurately from unsteady simulations of complicated flow field in blade rows. The period and scale of unsteady phenomena should be known for simulation in advance. In this study, the visualization system, which can visualize the unsteady flow phenomena during computation, has been applied to analyzing turbine flow field. The system which was conducted for multi-block parallel computing visualized effectively the unsteady flow behavior inside a turbine stage such as Karman vortex shedding, nozzle-rotor interaction, periodic separation occurrence on the rotor blade, etc. In this paper, the advantage of the visualization approach is clarified., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料

Inverse method is applied to geometry estimation of wind tunnel models. By defining the pressure distribution obtained from wind tunnel test as the target of inverse method, approximate geometry estimation is possible. The inverse method used in this paper is based on Takanashi's concept that utilizes integral equations and residual-correction technique. Geometry of two wind tunnel models were estimated. One is 23.5 percent scale and the other is 8.5 percent scale of NEXST-1 (National Experiment Supersonic Transport). The deviation of the estimated value from the original CATIA geometry was within a reasonable order if manufacturing limitation is considered. The geometry of the 8.5 percent scale wind tunnel model was measured for validation by using a non-contact three-dimensional measuring device employing laser beam and auto-focus system. The result shows the validity of the present method for approximate geometry estimation., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料

Development of Balloon-based Operation Vehicle (BOV) is currently in progress for the first flight scheduled in 2006. A vehicle in a wing-body configuration will be lifted by a high-altitude balloon and dropped. Various types of onboard experiments such as a microgravity experiment and a demonstration of a supersonic engine are planned during flights for the second, third and fourth flights. The aerodynamics load and characteristics of BOVs have been obtained by the CFD simulations as well as by the wind tunnel testing in ISAS. In this paper, the numerical simulations for BOV are presented and the results showed that the interaction between the wings, body and engine increases for transonic flow with high angle of attack., JAXA Special Publication, 宇宙航空研究開発機構特別資料

The SST (Shear-Stress Transport) turbulence model has been implemented in UPACS, a CFD platform developed in JAXA. Four test cases with increasing level of difficulty were used to validate the present implementation. Three basic test cases included flat plate, backward-facing step, and transonic airfoil RAE2822. For more practical application, the flow simulation around the DLR-F6 transport aircraft was performed. Validations were carried out by comparing the present numerical results with those of other numerical methods and experimental method. Numerical results obtained from the computations above show that the present implementation is valid. We believe that this effort has extended UPACS's applicability to more complicated flow fields., JAXA Special Publication, 宇宙航空研究開発機構特別資料

Thermocapillary-driven convection in a half-zone liquid bridge has been extensively examined. A large number of researches have been conducted concerning the transition of the flow field. Physical mechanism of the transition, however, has not been fully understood. In the present study, three-dimensional numerical simulations taking with and without Dynamic free Surface Deformation (DSD) into account are carried out to evaluate the effect of the surface deformation upon the flow field. The surface shape is solved by considering the stress balance on the free surface, and the calculation coordinate is reconstructed at every time step with employing a boundary fitted coordinate. The test fluids are acetone (Pr = 4.38) and 2cSt silicone oil (Pr = 28.11). The free surface deformation is determined primarily by the pressure variation. For acetone, the effect of the DSD upon critical point and flow field was quite small in the range of present numerical simulation in previous report. In this report, the effect of DSD for 2cSt silicone oil is obtained., JAXA Research and Development Report, 宇宙航空研究開発機構研究開発報告

Some years ago the national CFD project MEGAFLOW was initiated in Germany, which combines many of the CFD development activities from DLR, universities and aircraft industry. Its goal is the development and validation of a dependable and efficient numerical tool for the aerodynamic simulation of complete aircraft. The MEGAFLOW software system includes the block-structured Navier-Stokes code FLOWer and the unstructured Navier-Stokes code TAU. Both codes have reached a high level of maturity and they are being intensively used by the German aerospace industry in the design process of a new aircraft. This paper highlights recent improvements and enhancements of the software. Its capability to predict viscous flows around complex industrial applications for transport aircraft design is demonstrated., JAXA Special Publication, 宇宙航空研究開発機構特別資料

Recently CFD is commonly used in design, where high efficiency is required. The cartesian grid has an advantage over other grids because it is easy to generate grid. However, many grid cells are necessary to correctly capture various flow phenomena, which spoils the merit of the cartesian grid. In the present study, an LU-SGS method is employed for time integration to overcome this problem., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料

A brief review of the current capabilities and outstanding issues for the efficient analysis, and design of high-speed flight vehicles using unstructured grids is given. It is concluded that all major areas required in the analysis cycle - grid generation, flow solvers and visualization - have seen major advances in recent years. This trend is expected to continue, leading us to believe that turnaround in a matter of hours or minutes for complex geometries and/or physics will become a reality sometime in the next decade., JAXA Special Publication, 宇宙航空研究開発機構特別資料

This is a report on a multidisciplinary simulation software package, MUROS (MUltidisciplinary ROcket Simulation), which we have developed to be utilized in an ITBL (Information Technology Based Laboratory) environment, a virtual workspace on the Internet. In the ITBL environment, ITBL middleware manages the computer resources registered on the network and visualizes workflows. Hence, it is not necessary to be conscious of individual computer resources and application software can be run easily and effectively. MUROS software is used to predict processes from the launching of a rocket to the separation of booster rockets in the following steps. The first is estimation of thrust and drag by CFD (Computational Fluid Dynamics) analysis around the rocket. Next is the estimation of the rocket displacement by combining flight movement analysis with the thrust and drag., ITBL(Information Technology Based Laboratory)プロジェクトは、近年飛躍的にその帯域を広げてきた広域ネットワーク上に接続されているスーパーコンピュータやデータベースなどの計算資源を有効に活用するための仕組みと、その上で利用可能な計算科学アプリケーション・ソフトウェアを開発することを目的として2001年度から開始されたプロジェクトで、科学技術庁(現在は文部科学省)傘下の6機関が中心となって役割分担をしながら進めてきたものである。本報告は、この中でITBL環境において活用されるソフトウェアとして開発してきた、ロケット打ち上げ飛行シミュレーションソフトウェア(MUltidisciplinary ROcket Simulation: MUROS)についての報告である。MUROSはロケットの打ち上げから補助ロケットの分離までの過程をロケット周りの流体解析により推力と抵抗を推算し、飛行運動解析と組み合わせてロケットの運動を解析するためのソフトウェアである。ITBLの提供する基盤ソフトウェアとうまく組み合わせることにより、仮想化された環境の中で個々の計算機資源を意識することなく作業をすることができるようになり、ITBL環境を有効に活用することができる。本報告では、例題の結果を示した後、一連の操作方法の説明、プログラムについての簡単な説明を示す。例題としてはメインロケットの周りに補助ロケットが4本ついている形状を取り扱う。, JAXA Research and Development Memorandum, 宇宙航空研究開発機構研究開発資料

In order to investigate the capability of lifting body type atmospheric re-entry by relatively small-size vehicles, basic numerical and experimental study has been performed. The vehicle is based on the blunt nosed delta body with two tip fins. Two elevons are integrated on the fuselage base to enlarge trim capability for a wide range of Mach number flight. In the design of these lifting body type re-entry vehicles, one of the most important problems is that the vehicle has a capability to accomplish the stable flight from supersonic to low subsonic speeds. Aerodynamic characteristics have changed extremely through the transonic speed range. In the present study, conceptual aerodynamic analysis of these lifting re-entry vehicles has been performed by CFD and the wind tunnel experiments at NAL., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料

A flight test of a supersonic experimental airplane (NEXST-1: National EXperimental Supersonic Transport-1) was conducted successfully by JAXA in October 2005. In this study some aerodynamics design concepts were verified by comparing the flight test results with CFD (Computational Fluid Dynamics) analysis using JAXA's CFD codes, a structured mesh code UPACS (Unified Platform for Aerospace Computation Simulation) and an unstructured mesh code TAS (Tohoku university Aerodynamic Simulation). After the CFD codes was verified using a wind tunnel test results, the CFD results were compared with the flight test results. The aeroelastic deformation and the boundary layer transition data of flight test were taken into account to improve CFD analysis. The effect of the design concept of the NEXST-1 was also confirmed by CFD analysis., JAXA Special Publication, 宇宙航空研究開発機構特別資料

An aerodynamic design method has been developed by using a three-dimensional unstructured Euler code and an adjoint code with a discrete approach. The resulting adjoint code is applied to a wing design problem of supersonic transport with a wing-body-nacelle configuration. Hicks-Henne shape functions are adopted for the surface geometry perturbation, and the elliptic equation method is employed for the interior grid modification during the design process. Interior grid sensitivities are neglected except those for design parameters associated with nacelle translation. The Sequential Quadratic Programming method is used to minimize the drag with constraints on the lift and airfoil thickness. Successful design results confirm validity and efficiency of the present design method., JAXA Special Publication, 宇宙航空研究開発機構特別資料

JAXA Special Publication, 宇宙航空研究開発機構特別資料

Research in automatic grid generation around realistic 3D geometry is being conducted in Japan Aerospace Exploration Agency. This research aims at reducing the time required to generate computational grid for inviscid as well as viscous flow simulations. The method is based on hexahedra grid method, as the extension of Cartesian grid method. As the result, the method inherits significant advantages of Cartesian grid: it is automatic and fast. Because an efficient viscous flow simulation requires grid with high aspect ratio near solid surface, a hybrid with prismatic grid is necessary. The hexahedra grid extends naturally to this approach, because there is consistency in grid topology (both Cartesian and prismatic grids have the same hexahedral shape). The main idea of the method is as follows: construct Cartesian grid, remove the cells near solid surface, and construct hexahedral cells based on the Cartesian cells' faces toward the surface. Note that both grids are not constructed from the solid surface. This leads to another advantage: the method is not sensitive to defects in solid surface (e.g. crack, overlap), because it actually reconstruct the solid surface grid. However, because of the way the hexahedral cells are constructed (simple projection from Cartesian grid cells' faces toward solid surface), there is a disadvantage: it can not capture sharp concave features. A method to overcome this problem is devised in the present research. This paper provides the summary of the method being developed as well as some current results., JAXA Special Publication, 宇宙航空研究開発機構特別資料

READ (Reentry Environment Advanced Diagnostics) flight experiment was conducted by making use of the reentry phase of the USERS (Unmanned Space Experiment Recovery System) mission. In this experiment, the recovery module with 0.55 m nose radius was reentered with the velocity of 7.5 km/s, and the radiation spectrum along the stagnation line was obtained. At the high altitude (about 90 km), ablator originated species such as OH, CH, NH, which were not taken into consideration in the pre-flight prediction of the spectrum, were observed mainly. In this study, the effect of the ablator originated species on the spectrum were investigated by CFD analysis. In such high altitude, it is suggested that the role of the ablator originated species can not be negligible in contrast to the preflight prediction., USERSミッションでは再突入フェーズを利用して、再突入時に発生する衝撃層内の輻射光の分光スペクトル取得実験が行われた。再突入力プセルの先端ノーズ部半径は0.55mで、再突入速度は約7.5km/sであった。高度約90km付近で取得されたスペクトルからは、従来の予測では考慮されていなかったOH、NH、CHなどのアブレータと大気構成化学種との反応生成化学種からの発光が支配的であった。そこで、アブレーションを考慮したCFD解析を行い、その影響についての評価を試みた。その結果、壁面付近ではアブレータ起源化学種と大気構成化学種の反応化学種からの発光が無視できないほどの強度になることが示唆された。, JAXA Research and Development Report, 宇宙航空研究開発機構研究開発報告

JAXA Special Publication, 宇宙航空研究開発機構特別資料

This paper proposes a robust method to automatically generate unstructured hybrid grids comprised of tetrahedra, prisms, and pyramids for high Reynolds number viscous flow computations. The hybrid grid generation starts with isotropic tetrahedral grids to enhance the robustness of the algorithm. The tetrahedra near no-slip walls are shifted inward and the resulting gap between the tetrahedra and the walls is filled up with prismatic elements. The method is tested for experimental supersonic airplane models designed at the National Aerospace Laboratory of Japan (NAL). Aerodynamic coefficients by the Navier-Stokes equations are compared with wind tunnel data and the validity of the method is examined., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料

Based on Navier-Stokes equations and structural and flight dynamic equations of motion, dynamic responses in vertical gust flow perturbation are investigated for a supersonic transport. A tightly coupled method was developed by the subiteration between aerodynamic equations and dynamic equations of motion. First, the results of direct-coupling method are compared with the results of two model methods. Then gust responses for the one-minus-cosine gust profile are analyzed for the rigid and flexible airplane configurations., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料

SJAC (Society of Japanese Aerospace Companies) Phase-2 SST (SuperSonic Transport) configuration was designed by JADC (Japan Aircraft Development Corporation) SST working group. CFD (Computational Fluid Dynamics) analysis was conducted on the wing-body configuration to obtain preliminary aerodynamic data including non-linear effects such as transonic effect and so on, which are not counted in the primary design procedure. The results and the information obtained though this study are going to be discussed on this paper., JAXA Special Publication, 宇宙航空研究開発機構特別資料

The CFD and thermal coupling analyses system had been developed which software configuration was very compact to need less computational resource named CCAS (Compact Coupling Analyses System). A nodal method was applied for the thermal analyzer in the system because it essentially needed less memory resources and computation time, while a finite element method is generally used in other coupling analyses system. Also a set of assistance software was made that semi-automatically produced a thermal mathematical model from a CFD model to make a series of analyses work more efficient. A test analysis was done around H-2A 4S fairing during a flight. Heat flux at the stagnation point was compared with the value derived from theoretical equations, and analysis value was about 20 percent higher than from theoretical equations. Also compared were temperatures in the faring body with values of actual measurement at the first flight, and these from analysis were a little higher than actual. Although these calculation results of heat flux and temperatures from analysis indicated higher values, its differences were not so significant and were thought to be in the range of error by modeling uncertainty so the results from analysis were relatively correct and the system was confirmed to be valid., Special Publication of National Aerospace Laboratory, 航空宇宙技術研究所特別資料