1,960 research outputs found

    Integrated system to perform surrogate based aerodynamic optimisation for high-lift airfoil

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    This work deals with the aerodynamics optimisation of a generic two-dimensional three element high-lift configuration. Although the high-lift system is applied only during take-off and landing in the low speed phase of the flight the cost efficiency of the airplane is strongly influenced by it [1]. The ultimate goal of an aircraft high lift system design team is to define the simplest configuration which, for prescribed constraints, will meet the take-off, climb, and landing requirements usually expressed in terms of maximum L/D and/or maximum CL. The ability of the calculation method to accurately predict changes in objective function value when gaps, overlaps and element deflections are varied is therefore critical. Despite advances in computer capacity, the enormous computational cost of running complex engineering simulations makes it impractical to rely exclusively on simulation for the purpose of design optimisation. To cut down the cost, surrogate models, also known as metamodels, are constructed from and then used in place of the actual simulation models. This work outlines the development of integrated systems to perform aerodynamics multi-objective optimisation for a three-element airfoil test case in high lift configuration, making use of surrogate models available in MACROS Generic Tools, which has been integrated in our design tool. Different metamodeling techniques have been compared based on multiple performance criteria. With MACROS is possible performing either optimisation of the model built with predefined training sample (GSO) or Iterative Surrogate-Based Optimization (SBO). In this first case the model is build independent from the optimisation and then use it as a black box in the optimisation process. In the second case is needed to provide the possibility to call CFD code from the optimisation process, and there is no need to build any model, it is being built internally during the optimisation process. Both approaches have been applied. A detailed analysis of the integrated design system, the methods as well as th

    Aeronautical Engineering: A special bibliography with indexes, supplement 67, February 1976

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    This bibliography lists 341 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1976

    Advance survey and modelling technologies for the study of the slope stability in an Alpine basin

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    Alpine basins are typically characterised by an amphitheatre shape with steep rocky walls on the upper, a deposition zone of glacial debris in the middle and a channel in the lower part. All different parts are in constant evolution, and different kinds of instability phenomena can be identified: rock fall at the top rocky walls, rotational sliding of the deposit and debris flow in the channel down the valley. The different kinds of instability are somehow connected among them since the rock fall can power the rock debris that can trigger a debris flow. All different phenomena are chained in a global basin evolution also connected with seasonal climate variation that can induce different water presence and different water phase (liquid/solid). Moreover, instability phenomena seam to increase in frequencies and magnitudes in the latest decades possibly connected to climate change. This paper reports a study of the stability condition of an Alpine basin in North-West Italy by applying advance survey and modelling techniques: aerial photogrammetric survey of the rock wall, limit equilibrium methods that take ice presence into account and finally numerical analysis of the debris evolution along the slope. Parametric analyses aimed to quantify the influence of the different most important aspects have also been carried on. The application of advanced tools helped to better understand the study area failure and evolution mechanisms and to identify the main points to investigate in detail

    Aeronautical engineering: A continuing bibliography (supplement 152)

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    The bibliography lists 338 reports, articles and other documents introduced into the NASA scientific and technical information system in August 1982

    Fracture, Fatigue, and Structural Integrity of Metallic Materials and Components Undergoing Random or Variable Amplitude Loadings

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    Most metallic components and structures are subjected, in service, to random or variable amplitude loadings. There are many examples: vehicles subjected to loadings and vibrations caused by road irregularity and engine, structures exposed to wind, off-shore platforms undergoing wave-loadings, and so on. Just like constant amplitude loadings, random and variable amplitude loadings can make fatigue cracks initiate and propagate, even up to catastrophic failures. Engineers faced with the problem of estimating the structural integrity and the fatigue strength of metallic structures, or their propensity to fracture, usually make use of theoretical, numerical, or experimental approaches. This reprint collects a series of recent scientific contributions aimed at providing an up-to-date overview of approaches and case studies—theoretical, numerical or experimental—on several topics in the field of fracture, fatigue strength, and the structural integrity of metallic components subjected to random or variable amplitude loadings

    Aeronautical Engineering: A continuing bibliography with indexes, supplement 174

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    This bibliography lists 466 reports, articles and other documents introduced into the NASA scientific and technical information system in April 1984

    Aeronautical engineering: A continuing bibliography with indexes (supplement 258)

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    This bibliography lists 536 reports, articles, and other documents introduced into the NASA scientific and technical information system in October 1990. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

    Mathematical Modeling and Simulation in Mechanics and Dynamic Systems

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    The present book contains the 16 papers accepted and published in the Special Issue “Mathematical Modeling and Simulation in Mechanics and Dynamic Systems” of the MDPI “Mathematics” journal, which cover a wide range of topics connected to the theory and applications of Modeling and Simulation of Dynamic Systems in different field. These topics include, among others, methods to model and simulate mechanical system in real engineering. It is hopped that the book will find interest and be useful for those working in the area of Modeling and Simulation of the Dynamic Systems, as well as for those with the proper mathematical background and willing to become familiar with recent advances in Dynamic Systems, which has nowadays entered almost all sectors of human life and activity

    Aeronautical Engineering: A continuing bibliography with indexes, supplement 185

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    This bibliography lists 462 reports, articles and other documents introduced into the NASA scientific and technical information system in February 1985. Aerodynamics, aeronautical engineering, aircraft design, aircraft stability and control, geophysics, social sciences, and space sciences are some of the areas covered

    Aeronautical Engineering: A continuing bibliography with indexes

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    This bibliography lists 382 reports, articles and other documents introduced into the NASA scientific and technical information system in June 1982
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