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CFD計算の大規模化や一般化に伴い直交構造格子が広く利用されるようになっている。その理由としては計算対象の物体や流体現象に適合した格子の作成にかかる費用的・時間的コスト、計算実行時の計算速度における構造格子の優位さ等があげられる。しかし、直交構造格子の明らかな欠点として流れの方向や衝撃波面等の流体現象が格子との斜交により格子に適合しない場合には数値的な鈍化等の不都合が発生する事もよく知られる。これらの現象の説明として”数値粘性”というキーワードがよく用いられる。そのような説明でも現象論的にはある程度の説明ができ、不都合発生の機構についてそれなりの理解を与える面はあるが、未だに数学的な道具が不十分な事もあり、十分に明快な説明には至っていない場合も多い。このような現状では、数値計算で生じる不都合のそれぞれについてその発生機構の数理的考察を試みることも十分に意味があると考えられる。ここでは、1つの試みとして、流れの方向が格子、より厳密に言えば有限体積聞の境界面、に斜交する事によって数値的にはどのような効果が生じているのかを論ずる。, The cartesian grid is widely used in practical CFD computation nowadays. A few of the reasons are the large cost of curvilinear grid that can properly fit the object of computation and fluid phenomena and the advantage of structured grid in computation performance. On the other hand, the disadvantage in quality of computational result is well known. It is inevitable that the numerical result is blunted when the fluid phenomena, i.e. stream and shock surface etc., occur positioned obliquely to the mesh system. While such blunting effect is explained the technical term ‘numerical viscosity’, the machinery of numerical behavior is not yet precisely analysed. We do not have to enough mathematical tools to analyse and it is still impossible to give a clear explanation of the effect. In this article we show trial of analysis to give some explanation to the numerical effect., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

This paper describes CFD application examples to predict supersonic/transonic/subsonic aerodynamics in design studies of a Mars entry capsule for future Japan’s Mars exploration mission. Firstly, an example of the validation study for the JAXA’s in-house CFD code against aerodynamic database obtained by supersonic wind tunnel test is briefly presented. Subsonic, transonic, and supersonic flows around a 70 deg sphere-cone capsule model with support sting are simulated using large-eddy simulation (LES). The static aerodynamic coefficients obtained by LES show good agreement with the wind tunnel data. The obtained solutions by LES revealed the wake flow dynamics and their effects on the capsule aerodynamic characteristic. Secondly, the static aerodynamic simulations of sphere-cone shaped capsule and detached forebody aeroshell are conducted for supersonic and subsonic flight regimes near the parachute deployment point. The results demonstrated the capability of LES to predict the unsteady separated wake flows over sphere-cone shaped capsules. Finally, dynamic stability characteristic of a Mars entry capsule is investigated using LES. The dynamic simulations are conducted for the parachute deployment point at Mach 1.6. To investigate the influence on the dynamic stability characteristics, the moment of inertia is varied from 1 to 100 kg・m2. The preliminary results by the single degree-of-freedom simulations indicate that the dynamic stability characteristics are very sensitive to the moment of inertia., 会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-30日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

This paper describes CFD application examples to predict hypersonic aerothermodynamics in design studies of a Mars entry capsule for future Japan’s Mars exploration mission. Firstly, two examples of the validation studies for the JAXA’s in-house CFD code against experimental measurements are briefly presented. CFD predictions of aeroheating are conducted for the T5 shock tunnel experiment at California Institute of Technology. The CFD results are generally in good agreement with the experimental data and show that the effects of wall catalysis played an important role. Hypersonic flow simulations are conducted for an experimental measurement of RCS jet interactions performed on the JAXA hypersonic wind tunnel facility. By comparing the simulated aerodynamic coefficients with experimental data for jet-on and jet-off cases, fair agreements between the CFD and the experiment are achieved. After the accuracy of simulation is validated, the flowfield data are examined further in detail to understand the interaction mechanism between RCS jets and hypersonic wake flows. The features of the wake flow with the RCS jet injection are very similar to those observed in an under-expanded jet in a supersonic crossflow. Finally, for a preliminary design study of Mars entry capsule, a CFD prediction of aerothermodynamic environment in hypersonic lifting flight is demonstrated along the planned nominal entry trajectory., 会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-30日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

The article gives a brief report on the organized session 'Aeronautical Education Aid Forum'. This session is specialized in education aid activity using the software developed by JAXA. Recently, JAXA developed two numerical simulation tools for R&D, 'BOXFUN' and 'FaSTAR-Move', which will be used for education aid at universities as well. The main part of session is devoted to technical introduction of the tools. The annual activity of education aid is reported. The final part is discussion among the attendees., 会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-31日. 国際オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

The demand of Supersonic Transport (SST) is increasing globally. Some companies have announced their program for developing civil supersonic airplanes and the International Civil Aviation Organization (ICAO) has started developing the sonic boom standard for supersonic overland flight. Second AIAA Sonic Boom Prediction Workshop (SBPW2) has been held in January 2017 to assess the state of the art for predicting sonic boom. Japan Aerospace Exploration Agency (JAXA) designed a simple low boom configuration named 'JAXA Wing Body (JWB)' and provided it to the workshop for one of the test cases of SBPW2. For the validation of sonic boom prediction method, the supersonic wind-tunnel test of the JWB model was carried out at JAXA's supersonic wind-tunnel. This paper reports the development of an aeroelastic deforming estimation tool of the main wing in wind tunnel test and the results of CFD analysis for prediction of near-field sonic boom signature with aeroelastic deformation effects., 会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-34日. 国際オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

This paper describes the application of an adaptive mesh refinement method based on the block-based adaptation to the analysis of flow inside an engine cylinder. The suitability of the present AMR methodology, particularly of the time integration method and the effect of AMR to the computational results is shown. By comparing the results obtained using 1mm uniform mesh, 0.5mm uniform mesh, AMR mesh, we find the present block-based AMR method is effective for the high resolution of the flow analysis in the engine cylinder., 会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-40日. 国際オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-33日. 国際オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

A rotorcraft flow solver, rFlow3D, has been extended for ducted rotors. A circular grid topology has been implemented to enable a body grid solver to compute the duct shape. A background cylindrical grid is adopted for fine grid resolution of the clearance between the blade tip and the duct. Octree based interpolation processing is utilized for a fast interpolation between the body grid and the background cylindrical grid. The validation about the new adopted grid and the prediction accuracy of the ducted rotor performance is carried out based on an experiment of ducted rotor at Osaka University. A hovering rotor on a background cartesian and a cylindrical grid are simulated and compared reasonably well. The predicted ducted rotor performance is shown a good agreement with the experimental data., 会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-35日. 国際オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-30日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

The 'Post Limiter (simple a posteriori slope limiter),' which tries to keep spatially second order as much as possible, has been successfully extended to three-dimensional (3D) unstructured grids. Then, this 3D-extended version of Post Limiter ('Post Limiter 3') has been incorporated into 'FaSTAR,' a 3D unstructured grid flow solver. By taking account of cell-geometric qualities (i.e., aspect-ratio-like number), the Post Limiter 3 can handle general 3D cells including 'dirty' (=ill-shaped) ones in which the original Post Limiter fails to continue flow computations. Numerical examples demonstrate its applicability to a wide spectrum of aerodynamic problems of high engineering importance., 会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-42日. 国際オリンピック記念青少年総合センター), 渋谷区, 東京, 形態: カラー図版あり, Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

Physical characteristics: Original contains color illustrations, 会議情報: Third Aerodynamics Prediction Challenge (APC-III) ワークショップ (2017年6月28日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, Note: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム内で実施, 形態: カラー図版あり

Physical characteristics: Original contains color illustrations, 会議情報: Third Aerodynamics Prediction Challenge (APC-III) ワークショップ (2017年6月28日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, Note: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム内で実施, 形態: カラー図版あり

Physical characteristics: Original contains color illustrations, 会議情報: Third Aerodynamics Prediction Challenge (APC-III) ワークショップ (2017年6月28日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, Note: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム内で実施, 形態: カラー図版あり

Physical characteristics: Original contains color illustrations, 会議情報: Third Aerodynamics Prediction Challenge (APC-III) ワークショップ (2017年6月28日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, Note: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム内で実施, 形態: カラー図版あり

会議情報: Third Aerodynamics Prediction Challenge (APC-III) ワークショップ (2017年6月28日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, Note: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム内で実施, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

Physical characteristics: Original contains color illustrations, 会議情報: Third Aerodynamics Prediction Challenge (APC-III) ワークショップ (2017年6月28日. 国立オリンピック記念青少年総合センター), 渋谷区, 東京, Note: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム内で実施, 形態: カラー図版あり

In this work, a new Parametric Reduced-Order Model (PROM) with use of the Modally Equivalent Perturbed System (MEPS) and the Proper Orthogonal Decomposition (POD) is applied to unsteady flow about Airfoil with parameter variations in Mach. By applying the method, the original parameter-varied fluid system can be reduced from a very large dimension to a small dimension (e.g. for 2D case from 10,000 states to 100 states). While traditional Reduced-Order Model (ROM) cannot account for parameter variations, the present PROM is efficient to treat parameter changes adaptively. This means the POD modes obtained are valid for a wide range of parameter values. Towards this end, we have developed a frequency-domain CFD solver in which the fluid model is statically nonlinear, dynamically linearized (SNLDL) allowing unsteady simulations with small oscillations in subsonic, transonic, and supersonic flows in state-space format. With the state-space model, one can predict system responses (e.g. unsteady aerodynamic responses due to small amplitude oscillations of the lifting surface), conduct eigen-analysis, and build the PROMs. The ability of the new method to save substantial amount of computation for the varying parameter will be demonstrated using a 2D airfoil configuration., Meeting Information: First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

In many fluid-structure-interaction problems, the added mass is one of important interests. In the present study, we propose a simple and efficient method to specify fluid-force coefficients of a three-dimensional oscillating object in viscous fluid. The solving method is based on a discrete singularity method DSM. Then, we apply the DSM to some three-dimensional basic objects such as square-cross-section cylinders with various aspect ratios. Furthermore, we conduct experiments, and reveal the fluid-force coefficients of them comparing between computations and experiments, which show good agreement., Meeting Information: First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

More or less, the objectives of the engineering are to find optimal solution for the design of the products. Classically the variational methods have been used to find the optimal design in the engineering fields. So many numerical solutions are based upon the variational methods or its similar approaches even if the variational principle does not exist. Variational principles in the fluid dynamics has not been established yet, while those in elasticity and plasticity and optimal control theory have been highly confirmed and applied to actual problems. In this presentation, the methods of calculus variations are reviewed in the fields of structure and elasticity, optimal control theory and fluid dynamics. Firstly the fields of elasticity and optimal control theory are briefly reviewed. The details of them are not discussed here. Focusing on the fluid dynamics, a process of deriving the Hamilton’s principle is shown toward the applications for fluid-structure interaction problems like flutter or other interdisciplinary problems in engineering. The principle of virtual work is applied to the governing equations with boundary conditions. The conservation laws of mass and energy as well as the geometrical boundary conditions are treated as subsidiary conditions. In the present approach, a new concept of substantial variations of the state variables is introduced in order to describe the transportation terms and subsidiary conditions in a simple manner. It is a classical approach but might be useful for the development of computer aided design tools for aeroelasticity system and its optimal design., Meeting Information: First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

Wind-induced response/vibration of a bridge deck is governed by the surrounding flow field including flow separation and reattachment. It was also pointed out that the flow field is strongly affected by a small-scale turbulence component in an approaching flow. In wind-tunnel testing, in order to simulate turbulence effects, turbulence intensity is usually simulated. However the simulation of the power spectral density (PSD) of a small-scale turbulence component (high-frequency sub-inertia range), the so-called “turbulence partial simulation” may be a more rational way. In fact, past studies suggested that the turbulence partial simulation could give a better explanation for bridge deck vortex-induced vibration response between full scale and wind-tunnel test. In this study, using “reduced turbulence intensity”, the turbulence partial simulation was experimentally investigated for bluff-body structures. Results showed that reduced turbulence intensity could represent turbulence effects to the same degree as could turbulence intensity do. In addition, it was observed that a small-scale turbulence component governed the flow field around a bluff body., Meeting Information: First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

Since the Year 2002, the author has pointed out the historical mistakes of classic fluid dynamics theory and of vortex flow theory. A typical mistaken theory says that every vortex pair shall move at the fixed velocity (Γ/ 2π a ) relatively to the fluid filled static space and any vortex ring shall have their fixed self moving speed. Owing to author’s presentations over 13 years in international and domestic conferences, today, his discovery has been recognized almost all over the world especially among the specialists and authorities in this academic field. However, in spite of the crucial importance of the problem, his discovery has not yet been officially accepted nor recognized as a true. This paper may be the final presentation about the mistaken theory, because the mistakes are very simple as easy as to be understood by even high-school students when it is cleared. We must not hesitate to correct mistakes when we aware the facts., Meeting Information: First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

In the field of surgery the ability to handle organs and their associated systems in a stable yet delicate manner is of paramount importance for both the patient and the surgeon to ensure operation efficacy. This paper focuses on the development of flexible tipped surgical forceps. The mechanism is based on a previously developed “elastic vibration wing” which is biomimicry of the propulsion mechanism of a typical fish. The flexible forceps distributes pressure through a network of articulated linkages in order to softly envelop the object to be held. This mechanism was specifically designed for use in endoscopic surgery, however it could also be used in robotics where gentle grasp of an object is required at the end of a robotic arm. The mechanism was designed in 3D-CAD and conceptually prototyped using a 3D printer., Meeting Information: First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

Mach cones created by a falling sphere are observed experimentally in a viscoelastic fluid. The fluid used is a dilute wormlike micelle solution of cetyletrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) dissolved in water. The shear wave speed for the CTAB/NaSal solution is c approximately equal to 10 mm/s. A sphere falls through the fluid faster than the speed of shear waves. Mach cones are clearly observed in vorticity fields. They have a multiple-cone structure. The first cone is involved with forward shearing motion in the direction induced by the falling sphere, and it is followed by weaker cones with backward shearing motion accompanied by a relaxation of the initial shearing motion. The results suggest the importance of considering shear-wave-based Mach numbers that facilitates the understanding of a complex phenomenon associated with viscoelastic fluid flows., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 48th Fluid Dynamics Conference /the 34th Aerospace Numerical Simulation Symposium (July 6-8, 2016. The Kanazawa Theatre), Kanazawa, Ishikawa, Japan, Physical characteristics: Original contains color illustrations

The purpose of the present study about the supersonic parachute is to investigate the basic aerodynamic characteristics and the influences of perturbations by high-accuracy computation using the WENO scheme together with the HLLC flux Riemann solver. The simplified model with a rectangular concave shape is used without or with a sting model. The solutions for M∞=2.0 and M∞=3.0 are shown here. The Quasisteady flows are characterized by the detached bow shock wave from which vortices are shed and the shaking of the large subsonic region in the wake. The lift coefficients show fluctuations with low and high frequencies, and it has been indicated that the perturbations of inflow Mach number and the back pressure can cause oscillations of the detached bow shock waves. When the perturbation is impressed to the inflow Mach number, the location of the bow shock wave changes together with the pressure waves going and returning between the bow shock and the bottom of the concave body and the vortices shed from the center portion of the bow shock. When the sting is added to the concave body, the flow field suffers effects of the back pressure. Due to high back pressure, the thickness of boundary layer along the sting changes alternately in the upper and lower sides, with the position change of the bow shock., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 48th Fluid Dynamics Conference /the 34th Aerospace Numerical Simulation Symposium (July 6-8, 2016. The Kanazawa Theatre), Kanazawa, Ishikawa, Japan, Physical characteristics: Original contains color illustrations

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., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 48th Fluid Dynamics Conference /the 34th Aerospace Numerical Simulation Symposium (July 6-8, 2016. The Kanazawa Theatre), Kanazawa, Ishikawa, Japan, Physical characteristics: Original contains color illustrations

Fluid dynamics is the one of the key engineering issues in the space programs as it is important in the other engineering on the earth. CFD (Computational Fluid Dynamics) have already become an indispensable tool in the aerospace engineering, however, it was difficult to use CFD for core of space programs due to requirements for huge computer resources and complex physical modeling. to apply up to date CFD technology to space program for showing recent advancement., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 48th Fluid Dynamics Conference /the 34th Aerospace Numerical Simulation Symposium (July 6-8, 2016. The Kanazawa Theatre), Kanazawa, Ishikawa, Japan, Physical characteristics: Original contains color illustrations

A large-eddy simulation analysis solver using the multi-block grid with several block interface conditions is developed. The governing equations are the three-dimensional compressible Navier-Stokes equations in the generalized curvilinear coordinates. We adopt a sixth-order compact finite difference scheme for the convective and viscous terms and a fourth-order Runge-Kutta method for time integration. We introduce a block interface condition (BIC) that is newly developed and constructed based on the analogy between the finite volume scheme and the finite difference scheme. The BIC is compared with a characteristic based interface condition (CIC). We consider a single vortex convection crossing the boundary interface between the uniform Cartesian grid and the uniform Cartesian grid with considerable tilt as a test problem. Effects of strength of the vortex on the pressure distribution of the moving vortex are studied. A comparison of the pressure distribution of the vortex at the boundary interface presents that in the case of strong vortex the results of BIC are comparable to those of the CIC while in the case of weak vortex numerical oscillations are observed when the vortex crosses the interface. Furthermore, results obtained using the CIC and the BIC are considerably improved with increasing grid resolution in normal to the block interface., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 48th Fluid Dynamics Conference /the 34th Aerospace Numerical Simulation Symposium (July 6-8, 2016. The Kanazawa Theatre), Kanazawa, Ishikawa, Japan, Physical characteristics: Original contains color illustrations

Meeting Information: 48th Fluid Dynamics Conference /the 34th Aerospace Numerical Simulation Symposium (July 6-8, 2016. The Kanazawa Theatre), Kanazawa, Ishikawa, Japan, Physical characteristics: Original contains color illustrations, 会議情報: 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, 形態: カラー図版あり

会議情報: Second Aerodynamics Prediction Challenge (APC-II) ワークショップ (2016年7月6日. 金沢歌劇座), 金沢市, 石川, Note: 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内で実施, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

会議情報: Second Aerodynamics Prediction Challenge (APC-II) ワークショップ (2016年7月6日. 金沢歌劇座), 金沢市, 石川, Note: 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内で実施, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

会議情報: Second Aerodynamics Prediction Challenge (APC-II) ワークショップ (2016年7月6日. 金沢歌劇座), 金沢市, 石川, Note: 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内で実施, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

会議情報: Second Aerodynamics Prediction Challenge (APC-II) ワークショップ (2016年7月6日. 金沢歌劇座), 金沢市, 石川, Note: 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内で実施, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

会議情報: Second Aerodynamics Prediction Challenge (APC-II) ワークショップ (2016年7月6日. 金沢歌劇座), 金沢市, 石川, Note: 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内で実施, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

A numerical pressure estimation system which uses the 2.5 Dimensional model of a Poisson equation has been developed in order to let PIV measurement more advantageous in aerodynamic design. In the article, the system is examined if it can handle a case where the data of flow speed measured by PIV experiments have noise error. The examination is fully performed using computer simulation. First, the noise data of flow velocity are produced to add them to the original ideal velocity data. The several different error patters are prepared. Then, the pressure distributions are estimated by the system with the data in order to analyze how the noise errors affect the estimated results. The examination shows that boundary data imposed for the Poisson equation have great influence on the solutions all over the space. If a strategy is devised to reduce measurement errors on boundaries, fairly good pressure estimation can be done without caring the errors on inner space., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 47th Fluid Dynamics Conference /the 33rd Aerospace Numerical Simulation Symposium (July 2-3, 2015. Institute of Industrial Science , the University of Tokyo), Meguro, Tokyo, Japan, Physical characteristics: Original contains color illustrations

We are concerned with numerical computation of shocks whose surfaces are oblique to any axis of grid for computation, where the grid is a structured orthognal grid. It is easily observed that the capturing of shock surface is affected by the grid and that the surface often looks jagged but not smooth, even if the shock surface should be planar or smooth from theory. The phenomenon is purely numerical and the machinery of phenomenon is not yet clear. While the setting of problem is rather simple, several different mathematical factors are complicatedly related even in the case of compressible Euler equations for ideal gases. Therefore we analysis we still obtain some essential part of the numerical machinery, which may suggest a method to decrease the inconvenient effect of grid., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 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, Physical characteristics: Original contains color illustrations

This paper proposes WCNSCUZ which I adapted central difference and low dissipative weights to refer concepts of WENOCU and WENO-Z. WCNSCUZ is high resolution because interpolation of this scheme is applied central stencil constructed by upwind stencils and downwind stencil. Smoothness indicator of downwind stencil is obtained from central stencil, in order to solve discontinuity stable. Moreover, interpolation of 6th order WCNSCUZ completes enough accuracy in smooth region by using low dissipative weights. 6th order showed that WCNSCUZ achieves high resolution than 7th order classical robust WCNS and can give crisp result about discontinuity. However, present study has not enough evaluation about robustness of WCNSCUZ by variable interpolation., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 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, Physical characteristics: Original contains color illustrations

Spalart-Allmaras (S-A) model is one of the most widely used turbulence models is RANS-CFD. The S-A model is of one-equation model type, where the eddy viscosity transport equation is solved. However, the S-A model is constructed by including his intuition, analogy and empiricism. This makes it difficult to understand the model formalism and to modify the so as to be applied to the practical problems. In this paper, the S-A model is analysed from the standard and conventional turbulence modeling approach, and features of the model are clarified., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 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, Physical characteristics: Original contains color illustrations

To systematically investigate the aerodynamic characteristics of swept-back and forwarded wings with 0, 30, 45 and 60 degree of leading edge angles and different taper ratio, Navier-Stokes simulations for flows about a wing have been conducted. The Mach numbers of the flows are from 0.8 to 2.8. The planforms of wings are in various shapes whose aspect ratio is 2. The simulation and investigation has revealed new knowledge on the relation between swept or forwarded angles and aerodynamic characteristics of a wing in a supersonic flow. Not only a leading edge angle but also a trailing edge angle take important role on aerodynamics of a wing. In addition, transition from detached shockwaves to attached ones at the both edge largely affects the C(sub D)., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 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, Physical characteristics: Original contains color illustrations

In this paper, an immersed boundary method (IBM) and a cut-cell method on Cartesian grids are compared. In order to understand the characteristics of the two methods, two dimensional steady flow problems are solved. Near-wall pressure and shear stress distributions are investigated in detail. The results show that the cut-cell method is superior to IBM in grid convergence. However, the oscillation of the skin friction coefficient distributions is found in the cut-cell method, whereas IBM gives smooth distributions., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 47th Fluid Dynamics Conference /the 33rd Aerospace Numerical Simulation Symposium (July 2-3, 2015. Institute of Industrial Science , the University of Tokyo), Meguro, Tokyo, Japan, Physical characteristics: Original contains color illustrations

The aerodynamic performance of a full-scaled helicopter rotor is predicted using a rotorcraft CFD solver, rFlow3D. The prediction accuracy is verified through comparison with the selected wind tunnel test data of a constant thrust while the advance ratio is increased up to 0.4. Trim adjustment is improved by implementing a look-up table for the sectional aerodynamics. The rotor control angles and rotor drag and power between prediction and experiment are found in acceptable agreement. Some differences in the collective and lateral pitch angles are observed due to not including the elastic deformations in the analysis. Detailed comparisons of the sectional airloads are also performed and good correlations are found. The aerodynamic loads in the reversed flow region are also obtained. The influence of the elastic deformation on the prediction accuracy of aerodynamic performance at high advance ratio conditions will be further studied., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 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, Physical characteristics: Original contains color illustrations

Predicting buffet over an airfoil is one of the challenging problems for current CFD because the phenomenon is complex and unsteady. In this paper, we conduct a simulation of the transonic buffet over a super-critical airfoil using FaSTAR code which is the unstructured CFD code developed by JAXA. Zonal DES approach is employed for the flow simulations, which is RANS/LES hybrid approach. Results are compared with the past research and the experimental data., 会議情報: 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, 形態: カラー図版あり, Meeting Information: 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, Physical characteristics: Original contains color illustrations

会議情報: 第3回風洞技術の開発と応用シンポジウム: 風洞シンポジウム2014 (2014年10月24日. 日産自動車株式会社テクニカルセンター), 厚木市, 神奈川県, 形態: カラー図版あり, Meeting Information: Symposium on Developments and Applications of Wind Tunnel Technologies 3rd meeting (October 24, 2014. Advanced Technology Center, NISSAN MOTOR CO., LTD.), Atsugi, Kanagawa, Japan, Physical characteristics: Original contains color illustrations

会議情報: 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, 形態: カラー図版あり, 共同研究者: Harry A. Dwyer 他多数, Meeting Information: 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, Physical characteristics: Original contains color illustrations

会議情報: 第3回風洞技術の開発と応用シンポジウム: 風洞シンポジウム2014 (2014年10月24日. 日産自動車株式会社テクニカルセンター), 厚木市, 神奈川県, 形態: カラー図版あり, Meeting Information: Symposium on Developments and Applications of Wind Tunnel Technologies 3rd meeting (October 24, 2014. Advanced Technology Center, NISSAN MOTOR CO., LTD.), Atsugi, Kanagawa, Japan, Physical characteristics: Original contains color illustrations

形態: カラー図版あり, Physical characteristics: Original contains color illustrations

会議情報: First Aerodynamics Prediction Challenge (APC-I) ワークショップ (2015年7月3日. 東京大学生産技術研究所), 東京, Note: 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内で実施, 形態: カラー図版あり, Meeting Information: Aerodynamic Prediction Challenge workshop (APC-I) (July 3, 2015. Institute of Industrial Science, the University of Tokyo), Tokyo, Japan, Note: Workshop was held in 47th Fluid Dynamics Conference / 33nd Aerospace Numerical Simulation Symposium, Physical characteristics: Original contains color illustrations

会議情報: First Aerodynamics Prediction Challenge (APC-I) ワークショップ (2015年7月3日. 東京大学生産技術研究所), 東京, Note: 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内で実施, 形態: カラー図版あり, Meeting Information: Aerodynamic Prediction Challenge workshop (APC-I) (July 3, 2015. Institute of Industrial Science, the University of Tokyo), Tokyo, Japan, Note: Workshop was held in 47th Fluid Dynamics Conference / 33nd Aerospace Numerical Simulation Symposium, Physical characteristics: Original contains color illustrations

蒸気タービン，ガスタービン，風車，水車，原子力機器，発電機/モータなどの重電機器の開発にEFDとCFDを活用している．これまでに行ってきた蒸気タービン内の気液二相流の計測，カプラン水車の計測と解析の比較，および風車性能向上に向けたプラズマアクチュエータの開発計測などの具体例を紹介して，EFDとCFDのそれぞれに対する課題やこれらの融合技術に対する重電メーカからの期待について紹介する．, 会議情報: 第7回EFD/CFD融合ワークショップ (2015年1月26日. 秋葉原コンベンションホール), 千代田区, 東京, 形態: カラー図版あり, Meeting Information: The 7th Workshop on Integration of EFD and CFD (January 26, 2015. AKIHABARA Convention Hall), Chiyoda-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

近年、設計要求の多様化から複雑流動現象の解明が求められ、実験計測技術および数値計算技術に内在する不確実性への対処が求められるようになってきた。不確実性低減の取り組みとして、両技術を融合するデータ同化技術には大きな可能性がある。しかしながら、データ同化技術の工学分野への応用事例は限られており、また、工学分野の主目的である設計にデータ同化技術を活かすためのノウハウは全くと言っていいほど存在しない。本発表では、これまで発表者らが行ってきた航空・流体力学分野へのデータ同化の応用事例を紹介すると共に、現在、日本機械学会計算力学部門の下に企画している「設計に活かすデータ同化研究会」について説明する。, 会議情報: 第7回EFD/CFD融合ワークショップ (2015年1月26日. 秋葉原コンベンションホール), 千代田区, 東京, 形態: カラー図版あり, Meeting Information: The 7th Workshop on Integration of EFD and CFD (January 26, 2015. AKIHABARA Convention Hall), Chiyoda-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations

東日本大震災以降、我が国における火力発電の重要性は一層増加している。しかし、発電コスト低減の観点からは、燃料の多様化と更なる熱効率の向上が求められている。また、今後の再生可能エネルギーの導入に伴い、迅速な出力調整機能も求められる。このような課題を迅速かつ低コストに解.決する手段として、数値シミュレーションにかかる期待は大きい。しかし、火力発電所の機器内部は、高温や高圧な環境が多く、サブモデルの高度化は極めて困難である。また、機器内部の状態は種々の因子の影響を受ける。そのため、数値シミュレーションのみによって、火力機器内部の状態を予測・評価することは困難であると考えられる。このような状況を打破するためのブレークスルー技術として、データ同化手法への期待を述べる。, 会議情報: 第7回EFD/CFD融合ワークショップ (2015年1月26日. 秋葉原コンベンションホール), 千代田区, 東京, 形態: カラー図版あり, Meeting Information: The 7th Workshop on Integration of EFD and CFD (January 26, 2015. AKIHABARA Convention Hall), Chiyoda-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations