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AIAA Aviation Forum and Exposition

作者： Dwianto, Yohanes Bimo Fukumoto, Hiroaki Oyama, Akira Univ Tokyo Dept Aeronaut & Astronaut Tokyo 1138654 Japan Japan Aerosp Explorat Agcy Inst Space & Astronaut Sci Dept Space Flight Syst Sagamihara Kanagawa 2525210 Japan

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

In the present work, we propose an efficient infill criterion of surrogate model specifically for computationally expensive, severely-constrained optimization problems. Basing on a rank-based constraint handling technique (CHT) called multiple constraint ranking (MCR), we devise a rank-based infill criterion to overcome the drawbacks of the widely-known infill criterion called constrained expected improvement (CEI), namely CEI-MCR. In the framework of efficient global optimization (EGO), we conduct optimization on various kinds of benchmark problems to investigate the performance of the proposed infill criterion, CEI-MCR, compared with other currently existing infill criteria, CEI and EGOcons. Results of statistical significance tests on the optimization of the benchmark problems bring about a indication that the performance of CEI-MCR is either significantly more superior or equivalent compared with CEI and EGOcons by the end of EGO on all problems selected in the present work. In the last part of the present work, we conduct an airfoil design optimization and notice that CEI-MCR also performs with significant superiority or equivalently compared with CEI and EGOcons.

关键词： Surrogate Model NLF(1) 0416 Aerodynamic Properties Aerodynamic Performance Cumulative Distribution Function computational Fluid dynamics Evolutionary Algorithm computational structural dynamics Boundary Layer Equations Bayesian Optimization

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Gradient-Based Propeller Optimization with Acoustic Constraints

Gradient-Based Propeller Optimization with Acoustic Constrai...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Ingraham, Daniel Grayt, Justin Lopest, Leonard, V NASA Glenn Res Ctr Acoust Branch MS 54-3 Cleveland OH 44135 USA NASA Glenn Res Ctr Prop Syst Anal Branch MS 5-11 Cleveland OH 44135 USA NASA Langley Res Ctr Aeroacoust Branch MS 461 Hampton VA 23681 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

Urban Air Mobility vehicles are intended to operate near or within large cities, where a significant portion of the public will be exposed to the noise they create. If these vehicles are to become acceptable to the public, designers must be able to manage the amount of noise they generate, and understand the relationship between traditional performance metrics (thrust, efficiency, etc.) and noise. As a first step to addressing this need, this work combines a blade element momentum theory tool (OpenBEMT) with an acoustic prediction tool (ANOPP2) to optimize a propeller subject to both aerodynamic and acoustic constraints. These tools are developed within a optimization framework (OpenMDAO) that allows analytic derivatives to be propagated through the models and passed to a gradient-based optimizer. This toolchain is exercised on the cruise propellers from the X-57 Maxwell, and yields propeller designs that reduced the overall sound pressure level by about 5 dB for a cost of 1% propeller efficiency.

关键词： Propeller Performance Urban Air Mobility Blade Element Momentum Theory computational Fluid dynamics Aerodynamic Force Aerodynamic Performance Power Generation National Renewable Energy Laboratory computational structural dynamics Pusher Configuration

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Fluid-Structure Interactions with Geometrically Nonlinear Deformations

Fluid-Structure Interactions with Geometrically Nonlinear De...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Boustani, Jonathan Browne, Oliver M. F. Wenk, Jonathan F. Barad, Michael F. Kiris, Cetin C. Brehm, Christoph Univ Kentucky Dept Mech Engn Lexington KY 40506 USA NASA Computat Aerosci Branch Ames Res Ctr Moffett Field CA 94035 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

A numerical method for simulating fluid-structure interaction problems involving large, geometrically nonlinear deformations is presented. In this method, a proven computational fluid dynamics solver based on a higher-order immersed boundary method is coupled with a geometrically nonlinear structural finite element solver. The finite element solver employs the mixed interpolation of tensorial components formulation for shell elements. The implementation of the finite element solver and validation results for geometrically nonlinear test problems are discussed. Details of the coupling approach used to transfer loads and displacements between the fluid dynamic and finite element solvers are also presented. The fully-coupled fluid-structure interaction method is then applied to problems with large, geometrically nonlinear deformations, such as a cylinder with a flexible trailing filament, a hyperelastic bending tower, a compliant disk in a viscous flow, and a waving flag.

关键词： Fluid Structure Interaction Finite Element Formulation computational Fluid dynamics Flow Conditions computational structural dynamics Elastic Modulus Bernoulli Euler Beams Triangular Element Kinematic Viscosity Flow Visualization

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A Time-Marching Aeroelastic Method Applied to Propeller Flutter

A Time-Marching Aeroelastic Method Applied to Propeller Flut...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Higgins, Ross J. Jimenez-Garciat, Antonio Barakos, George N. Bowtell, Nicholas Univ Glasgow CFD Lab James Watt South Bldg Glasgow G12 8QQ Lanark Scotland Dowty Propellers Anson Business PkCheltenham Rd East Gloucester GL2 9QN England

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

A time-marching aeroelastic method developed for the study of propeller flutter is presented and validated. Propeller flutter can take many forms with stall, whirl and classical flutter being the primary responses. These types of flutter require accurate capture of the non-linear aerodynamics associated with propeller blades. Stall flutter in particular, due to the highly detached nature of the flow, needs detailed unsteady flow modelling. With the development of modern propeller designs potentially adjusting the flutter boundary and the development of faster computing power, CFD is required to ensure accurate capture of aerodynamics. This paper focuses on the validation of the aeroelastic method using the Commander propeller blade.

关键词： Propeller Performance computational Fluid dynamics Dynamic Stall Aeroelastic Response Computing Power Flow Conditions Reynolds Averaged Navier Stokes Vortices computational structural dynamics Arbitrary Lagrangian Eulerian

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Fully-Coupled Fluid-Structure Interaction Simulations of a Supersonic Parachute

Fully-Coupled Fluid-Structure Interaction Simulations of a S...

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AIAA Aviation Forum and Exposition

作者： Boustani, Jonathan Barad, Michael F. Kiris, Cetin C. Brehm, Christoph Univ Kentucky Dept Mech Engn Lexington KY 40506 USA NASA Ames Res Ctr Computat Aerosci Branch Moffett Field CA 94035 USA

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

A validated computational fluid-structure interaction method for simulating the complex interaction between the large deformation of very thin, highly deformable structures and compressible flows is extended to consider large-scale problems in supersonic flows using parallel computing. The coupled fluid-structure interaction system is solved in a partitioned, or weakly-coupled, manner. The foundations of the applied fluid-structure interaction method are a higher-order, block-structured Cartesian, sharp immersed boundary method for the compressible Navier-Stokes equations and a computational structural dynamics solver employing a geometrically nonlinear 3-node shell element based on the mixed interpolation of tensorial components formulation. The method is applied to large deformation fluid-structure interaction validation cases before being applied to the inflation of a supersonic parachute in the upper Martian atmosphere where the goal is to demonstrate the capabilities of the solver when considering large-scale problems in supersonic flows.

关键词： computational Fluid Structure Interaction computational structural dynamics computational Fluid dynamics Compressible Flow Navier Stokes Equations Parallel Computing Supersonic Inflatable Aerodynamic Decelerator Adaptive Mesh Refinement Finite Element Formulation structural Response

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Aeroelastic Study of the Splitter Plate in Turbine-Based Combined-Cycle Inlet

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JOURNAL OF AIRCRAFT 2018年第5期55卷 1914-1928页

作者： Qin, Qihao Xu, Jinglei Guo, Shuai Nanjing Univ Aeronaut & Astronaut Coll Energy & Power Engn Nanjing 210016 Jiangsu Peoples R China

A two-dimensional over-under turbine-based combined-cycle inlet system that exhibits the fluid-structure interaction phenomenon is investigated at both design and off-design states. The mesh-based parallel code coupling interface is used to perform a two-way loosely coupled data exchange across the fluid-structural interfaces. Results indicate that, although the performance variation is limited at a ramjet mode with Ma(0) = 2.5, unexpected limit cycle oscillations appear accompanied by unsteady amplitudes. Moreover, a remarkable unstart delay along with the deceleration process of performance deterioration can be observed when the backpressure goes through a rapid increase, where the upward deformation of the splitter plate plays a significant role in resisting the downstream disturbance. In contrast, the fluid-structure interaction effect leads to an earlier occurrence of inlet unstart when the angle of attack varies periodically, and it induces limit cycle oscillations at a higher varying frequency. The study reveals the necessity of attaching more importance to the aeroelastic behavior of the splitter plate in the future research and operation of the over-under turbine-based combined-cycle inlet system.

关键词： Turbine Based Combined Cycle FSI Angle of Attack Ramjet Engines Turbojet Engine Aerodynamic Force Vector Arbitrary Lagrangian Eulerian computational structural dynamics FLUENT Mass Flow Rate

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Feasible Probabilistic Learning Method for Model-Form Uncertainty Quantification in Vibration Analysis

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AIAA JOURNAL 2019年第11期57卷 4978-4991页

作者： Farhat, Charbel Tezaur, Radek Chapman, Todd Avery, Philip Soize, Christian Stanford Univ Aircraft Struct Dept Aeronaut & Astronaut Durand BldgRoom 257 Stanford CA 94305 USA Stanford Univ Dept Aeronaut & Astronaut Durand BldgRoom 257 Stanford CA 94305 USA US Army Res Lab Adelphi MD 20783 USA Univ Paris Est Marne Vallee Lab Modelisat & Simulat Multi Echelle Equipe Meca 5 Blvd Descartes F-77454 Marne La Vallee 2 France

Recently, a novel probabilistic method for modeling and quantifying model-form uncertainties in a deterministic high-dimensional computational model was proposed and demonstrated for numerous applications in linear vibrations and nonlinear structural dynamics. The method relies on a stochastic projection-based reduced-order model (SPROM) grounded in a randomized reduced-order basis to accelerate the stochastic computations it incurs, and it accounts for all modeling uncertainties introduced by model reduction. It builds the probability model of the SPROM using a small number of hyperparameters, and it determines them so that the mean value and statistical fluctuations of quantities of interest predicted using the SPROM match target values obtained from available data. Hence, it can be interpreted as a probabilistic model learning or updating method. Unfortunately, even though it is performed using a reduced-order model, the hyperparameter identification process can be cost prohibitive. For this reason, the method is reformulated in this paper around the concept of hyper-reduction. Specifically, a reduced version of the mesh underlying the high-dimensional model is constructed and used to hyper-reduce the SPROM. The feasibility of the resulting approach is demonstrated for the model-form uncertainty quantification of generalized eigencomputations performed during what-if scenarios associated with shape changes of a jet engine nozzle.

关键词： computational structural dynamics Jet Engines structural Vibration Stiffness Matrices Probability Distribution Greedy Algorithm Singular Value Decomposition Stochastic Optimization Model Order Reduction structural Modeling

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US Army Rotorcraft Research at Ames: New Frontier in dynamics and Aeroelasticity

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AIAA JOURNAL 2019年第10期57卷 4312-4327页

作者： Ormiston, Robert A. Peters, David A. US Army Aviat Dev Directorate Ames Aviat & Missile Ctr US Army Combat Capabil Dev Command Moffett Field CA 94035 USA Washington Univ St Louis MO 63130 USA

This paper presents an informal narrative of rotorcraft structural dynamics and aeroelasticity research initiated by the U.S. Army at NASA Ames Research Center in the early 1970s, when rotorcraft research became something of a new frontier in aerospace. The paper is focused on research conducted by Dewey Hodges and the authors, and it is based on a paper given as a tribute for the Dewey70 Session of the 2018 AIAA SciTech Forum. This rotorcraft research contributed a rigorous theoretical foundation that helped transform rotorcraft analysis from uncertainty into today's sophisticated methodology that provides a sound basis for modern rotorcraft design. Dewey Hodges was arguably one of the principal architects of this transformation. Selected material is presented on the development of nonlinear beam theory for rotor blades, applications to rotorcraft aeroelastic stability, and experimental validation studies. The paper concludes by showing how these methods have been linked with today's modern rotorcraft computational fluid dynamics.

关键词： Dynamic Aeroelastic Analysis Rotorcraft Simulations Hingeless Rotor Blade computational structural dynamics CFD NASA Ames Research Center Articulated Rotor Pitching Moment Flight Test Programme Fuselages

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Downburst-induced transient response of a long-span bridge: A CFD-CSD-based hybrid approach

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JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AEROdynamics 2018年 179卷 273-286页

作者： Hao, Jianming Wu, Teng SUNY Buffalo Dept Civil Struct & Environm Engn 115 Ketter Hall Buffalo NY 14260 USA SUNY Buffalo Dept Civil Struct & Environm Engn 226 Ketter Hall Buffalo NY 14260 USA

The long-span bridges, frequently located in the coastline and mountainous areas, are prone to suffering from the transient downburst winds associated with the thunderstorms. Therefore, it is important to examine the behaviors of long-span bridges under such wind events. In this study, the time history of non-turbulent downburst wind field is modeled using the impinging jet-based computational fluid dynamics (CFD) approach. It has demonstrated high-fidelity simulations of the downburst wind field, especially for the near-surface radial winds that are particularly significant for present investigation of bridge aerodynamics and aeroelasticity, with a reasonable computational cost. The simulated time-varying mean wind velocity field of a typical downburst event is validated using available field measurements. The correlated nonstationary fluctuations of the downburst are stochastically simulated by the Hilbert-wavelet scheme based on full-scale data, and then superimposed onto the CFD-based transient mean wind field. The obtained turbulent downburst wind field is employed as the dynamic inputs to the line-element-based three-dimensional (3-D) finite element model of the long-span bridge, and its downburst-induced transient response is acquired using the computational structural dynamics (CSD) approach. The aerodynamic and aeroelastic couplings between the downburst winds and the long-span bridge are modeled using the two-dimensional (2-D) indicial response functions that could well represent the transient bridge aerodynamics under non-synoptic winds. The time-domain buffeting response analysis of a long-span suspension bridge under the traveling downburst has been carried out utilizing the CFD-CSD-based hybrid methodology. The results highlight the importance of the transient and nonstationary effects on the non-synoptic wind-induced structural dynamic response.

关键词： Downburst winds Long-span bridge computational fluid dynamics computational structural dynamics Transient aerodynamics

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High-Fidelity computational Fluid dynamics Methods for the Simulation of Propeller Stall Flutter

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AIAA JOURNAL 2019年第12期57卷 5281-5292页

作者： Higgins, Ross J. Jimenez-Garcia, Antonio Barakos, George N. Bown, Nicholas Univ Glasgow CFD Lab James Watt South Bldg Glasgow G12 8QQ Lanark Scotland Dowty Propellers Anson Business PkCheltenham Rd East Gloucester GL2 9QN England

A time-marching aeroelastic method developed for the study of propeller flutter is presented and validated. Propeller flutter can take many forms, with stall, whirl, and classical flutter being the primary responses. These types of flutter require accurate capture of the nonlinear aerodynamics associated with propeller blades. Stall flutter in particular needs detailed unsteady flow modeling. With the development of modern propeller designs potentially adjusting the flutter boundary and the development of faster computing power, computational fluid dynamics is required to ensure accurate capture of aerodynamics. Given the lack of reliable experimental stall flutter data for propellers, the method was focused on observing the correct qualitative behavior with a comparison made between unsteady Reynolds-Averaged Navier-Stokes and scale-adaptive simulations.

关键词： Aeroelastic Response Propeller Blades Courant Friedrichs Lewy Aerodynamic Damping Reynolds Averaged Navier Stokes Flow Conditions Computing Power computational structural dynamics Pitching Airfoil Finite Element Modeling

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