Time-dependent aeroelastic simulation of rapid manoeuvring aircraft

Fornasier, L.; Rieger, H.; Tremel, Udo; Weide, Edwin van der

doi:10.2514/6.2002-949

Cited by 17 publications

(7 citation statements)

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“…Given the CAD definition of the geometry and a set of explicitly constructed far-field boundaries, Centaur uses an advancing-front method to generate both surface and volume meshes. Once a suitable mesh has been generated, the flow solution is carried out using the AirplanePlus solver of Fornasier et al [17], which uses an agglomeration multigrid strategy and MPI-based (message passing interface) parallelization to solve Reynoldsaveraged Navier-Stokes (RANS) equations on unstructured tetrahedral meshes. Although the software is able to solve the RANS equations, all calculations in this work have been carried out using the Euler equations because the phenomena that result in ground boom signatures (shock waves and expansions) are largely of an inviscid nature, and no regions of separated flow were observed in the experiments.…”

Section: Methodology: Boom Unstructured Adaptivementioning

confidence: 99%

“…The three-dimensional AirplanePlus flow solver of Fornasier et al [17] is used, which is a C implementation of the original AIRPLANE flow solver of Jameson et al [30]. AirplanePlus contains substantial enhancements to the baseline algorithm, the agglomeration multigrid strategy, parallelization (of both the solver and preprocessor), load balancing algorithm, and the solution of the RANS equations.…”

Section: B Unstructured Flow Solver and Solution Approachmentioning

confidence: 99%

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Numerical and Mesh Resolution Requirements for Accurate Sonic Boom Prediction

Choi

Alonso

Weide

2009

Journal of Aircraft

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A careful study is conducted to assess the numerical mesh resolution requirements for the accurate computation of sonic boom ground signatures produced by complete aircraft configurations. The details of the ground signature can depend heavily on the accurate prediction of the pressure distribution in the near field of the aircraft. It is, therefore, important to accurately describe the geometric details of complete configurations (including the wing, fuselage, nacelles, diverters, etc.) and to precisely capture the propagation of shock and expansion waves at large distances from the aircraft. Unstructured, adaptive mesh technologies are ideally suited for this purpose as they use mesh points only in the appropriate locations within the flowfield. In this work, we consider a supersonic business jet configuration that was tested at the NASA Langley Research Center. Near-field data were measured at several locations underneath the flight track. The propagation of these near-field signatures from different altitudes can be shown to result in near N-wave ground booms. To examine the effect of both nacelles and empennage, results for three test cases are presented. These test cases represent the complete configuration, the configuration without the nacelles, and the configuration without the nacelles and empennage. Inviscid solution-adaptive unstructured meshes with up to 7.2 million nodes and 42.1 million tetrahedra are used to calculate the pressure distributions at several locations below each configuration where comparisons with experimental data are performed. All near-field pressure distributions are propagated to the ground (from an altitude of 50,000 ft) to predict the ground boom and the perceived noise level of the ground signature. Both the near-field overpressures and ground boom signatures are compared between experimental data and computational fluid dynamics simulation, and the results show good agreement in all cases. The minimum number of mesh nodes and elements and the levels of refinement needed for the accurate computations of near-field pressure distribution and ground boom signature are discussed for each of the three cases. Nomenclature C L = lift coefficient c = speed of sound L = aircraft body length p = pressure p 1 = freestream pressure R = distance from the aircraft normal to the body axis S ref = reference area V = velocity vector △p o = initial pressure rise △x = local grid length scale = adaptation function 0 = adaptation function with local mesh length scale rp = pressure difference

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Section: Methodology: Boom Unstructured Adaptivementioning

confidence: 99%

Section: B Unstructured Flow Solver and Solution Approachmentioning

confidence: 99%

Numerical and Mesh Resolution Requirements for Accurate Sonic Boom Prediction

Choi

Alonso

Weide

2009

Journal of Aircraft

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“…Hal ini bertujuan untuk mengetahui frekuensi, massa, dan kekakuan termampatkan tiap modus gerak [20]. Rentang frekuensi modus gerak yang digunakan dalam analisis dinamik adalah rentang frekuensi optimum [21], dimana pada penelitian sebelumnya diperoleh rentang frekuensi 0-1036 Hz [1].…”

Section: Metode Penelitianunclassified

Flutter Analysis of RX-420 Balistic Rocket Fin Involving Rigid Body Modes of Rocket Structures

Andria

2013

MST

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AbstrakFlutter adalah suatu fenomena yang menyebabkan kegagalan katastropik pada struktur wahana terbang. Pada penelitian ini, flutter dikaji untuk konfigurasi simetri dan antisimetri untuk mengetahui pengaruh modus gerak kaku struktur roket terhadap karakteristik flutter sirip roket. Melalui penelitian ini diharapkan pula tingkat keamanan desain struktur roket RX-420 terhadap flutter dapat diketahui. Model yang dianalisis merupakan model setengah bagian roket. Struktur sirip yang digunakan adalah sirip dengan semispan 600 mm, tebal 12 mm, root 700 mm, tip 400 mm, jenis bahan Al 6061-T651 berkonfigurasi sirip double spar dengan ketebalan kulit sirip 2 mm. Dinamika struktur roket dan kestabilan flutter-nya dianalisis dengan menggunakan metode elemen hingga yang terimplementasi pada software MSC NASTRAN. Analisis menunjukkan bahwa flutter pada sirip lebih rentan terjadi pada konfigurasi antisimetri dibandingkan dengan konfigurasi simetri. Untuk konfigurasi antisimetri flutter terjadi pada kecepatan 6,4 Mach sedangkan untuk konfigurasi simetri flutter terjadi pada 10,15 Mach pada ketinggian permukaan laut. Bila dibandingkan dengan nilai kecepatan maksimum roket sebesar 4,5 Mach pada ketinggian 11 km atau ekivalen dengan 2,1 Mach pada ketinggian permukaan laut, maka dapat disimpulkan bahwa desain struktur roket RX-420 memenuhi batas keamanan dan flutter tidak akan terjadi selama roket terbang. Abstract Flutter Analysis of RX-420 Balistic Rocket Fin Involving Rigid Body Modes of Rocket Structures.Flutter is a phenomenon that has brought a catastrophic failure to the flight vehicle structure. In this experiment, flutter was analyzed for its symmetric and antisymmetric configuration to understand the effect of rocket rigid modes to the fin flutter characteristic. This research was also expected to find out the safety level of RX-420 structure design. The analysis was performed using half rocket model. Fin structure used in this research was a fin which has semispan 600 mm, thickness 12 mm, chord root 700 mm, chord tip 400 mm, made by Al 6061-T651, double spar configuration with skin thickness of 2 mm. Structural dynamics and flutter stability were analyzed using finite element software implemented on MSC. Nastran. The analysis shows that the antisymmetric flutter mode is more critical than symmetric flutter mode. At sea level altitude, antisymmetric flutter occurs at 6.4 Mach, and symmetric flutter occurs at 10.15 Mach. Compared to maximum speed of RX-420 which is 4.5 Mach at altitude 11 km or equivalent to 2.1 Mach at sea level, it can be concluded that the RX-420 structure design is safe, and flutter will not occur during flight.

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“…The three-dimensional, unstructured, tetrahedral AirplanePlus flow solver is used in this work. Airplane-Plus is a C++ solver written by van der Weide [26] which uses an agglomeration multigrid strategy to speed The addition of pylons to support the nacelles and of power effects only serve to complicate the flow patterns further. This type of flow pattern can be hard to understand, particularly in the context of sonic boom computations.…”

Section: B Tetrahedral Unstructured Mesh Generation and Euler Flow Smentioning

confidence: 99%

“…A hierarchical, multi-fidelity response surface generation technique that uses results from classical supersonic aerodynamics, a linearized supersonic panel code (A502/Panair [25]), and an unstructured adaptive Euler solver (AirplanePlus [26]) to create models of the aerodynamic performance. The summary of the hierarchy of the analysis and design tools used in our study is shown at Table 1, and computation time for each analysis is also compared.…”

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confidence: 99%

Two-Level Multi-Fidelity Design Optimization Studies for Supersonic Jets

Choi

Alonso

Kim

et al. 2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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The conceptual/preliminary design of superonic jet configurations requires multi-disciplinary analyses (MDAs) tools which are able to provide a level of flexibility that permits the exploration of large areas of the design space. High-fidelity analysis for each discipline is desired for credible results, however, corresponding computational cost can be prohibitively expensive often limiting the the ability to make drastic modifications to the aircraft configuration in question. Our work has progressed in this area, and we have introduced a truly hybrid, multi-fidelity approach in MDAs and demonstrated, in previous work, its application to the design optimization of low-boom supersonic business jet. In this paper we extend our multi-fidelity approach to the design procedure and present two-level design of a supersonic business jet configuration where we combine a conceptual low-fidelity optimization tool with a hierarchy of flow solvers of increasing fidelity and advanced adjoint-based Sequential Quadratic Programming (SQP) optimization approaches. In this work, we focus on the aerodynamic performance aspects alone: no attempt is made to reduce the acoustic signature. The results show that this particular combination of modeling and design techniques is quite effective for our design problem and the ones in general, and that highfidelity aerodynamic shape optimization techniques for complex configurations (such as the adjoint method) can be effectively used within the context of a truly multi-disciplinary design environment. Detailed configuration results of our optimizations are also presented.in the design and use relative inexpensive multi-disciplinary analyses (MDAs). Preliminary design tools incorporate higher levels of fidelity (particularly in the aerodynamics) but can be quite costly. Traditionally it has been sufficient to follow a sequential process by which a rough configuration is developed during the conceptual design phase and it is later refined using preliminary design tools. The key question that we are revisiting in this paper is whether this sequential conceptual/preliminary design process is adequate for supersonic aircraft when the participating disciplines are closely coupled or whether higher-fidelity tools need to been included early on to ensure that the outcome of the conceptual designs can be believable and used for further design work. In some senses, we are proposing to merge the first two phases of the design, conceptual and preliminary, into a single one while ensuring that both the solution accuracy and turnaround time are acceptable to the aircraft designer.There are, however, some fundamental problems in integrating conceptual and preliminary design tools.At the conceptual stage we have traditionally integrated a large number of disciplinary models of low-tomedium fidelity coupled into a single multi-disciplinary analysis. The range of variation in the design variables is typically set large enough to cover large areas of design space. The nature of the resulting design space is o...

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Time-dependent aeroelastic simulation of rapid manoeuvring aircraft

Cited by 17 publications

References 4 publications

Numerical and Mesh Resolution Requirements for Accurate Sonic Boom Prediction

Numerical and Mesh Resolution Requirements for Accurate Sonic Boom Prediction

Flutter Analysis of RX-420 Balistic Rocket Fin Involving Rigid Body Modes of Rocket Structures

Two-Level Multi-Fidelity Design Optimization Studies for Supersonic Jets

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