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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781726187213
Category :
Languages : en
Pages : 56
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Book Description
This report summarizes the activities in unsteady aerodynamic modeling and application of unsteady aerodynamic models to flight dynamics. A public on briefing was presented on July 21, 1999 at Langley Research Center.Lan, C. EdwardLangley Research CenterAERODYNAMIC CHARACTERISTICS; FLIGHT CONDITIONS; UNSTEADY AERODYNAMICS; MATHEMATICAL MODELS; FUZZY SYSTEMS; FLOW DISTRIBUTION; CONVOLUTION INTEGRALS; NONLINEARITY; FOURIER ANALYSIS...
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781726187213
Category :
Languages : en
Pages : 56
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Book Description
This report summarizes the activities in unsteady aerodynamic modeling and application of unsteady aerodynamic models to flight dynamics. A public on briefing was presented on July 21, 1999 at Langley Research Center.Lan, C. EdwardLangley Research CenterAERODYNAMIC CHARACTERISTICS; FLIGHT CONDITIONS; UNSTEADY AERODYNAMICS; MATHEMATICAL MODELS; FUZZY SYSTEMS; FLOW DISTRIBUTION; CONVOLUTION INTEGRALS; NONLINEARITY; FOURIER ANALYSIS...
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722380052
Category :
Languages : en
Pages : 48
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Book Description
A nonlinear least squares algorithm for aircraft parameter estimation from flight data was developed. The postulated model for the analysis represented longitudinal, short period motion of an aircraft. The corresponding aerodynamic model equations included indicial functions (unsteady terms) and conventional stability and control derivatives. The indicial functions were modeled as simple exponential functions. The estimation procedure was applied in five examples. Four of the examples used simulated and flight data from small amplitude maneuvers to the F-18 HARV and X-31A aircraft. In the fifth example a rapid, large amplitude maneuver of the X-31 drop model was analyzed. From data analysis of small amplitude maneuvers ft was found that the model with conventional stability and control derivatives was adequate. Also, parameter estimation from a rapid, large amplitude maneuver did not reveal any noticeable presence of unsteady aerodynamics. Klein, Vladislav and Noderer, Keith D. Langley Research Center RTOP 505-64-52-01...
Author: Mehdi Ghoreyshi
Publisher: MDPI
ISBN: 3038976105
Category : Technology & Engineering
Languages : en
Pages : 294
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Book Description
Currently, the use of computational fluid dynamics (CFD) solutions is considered as the state-of-the-art in the modeling of unsteady nonlinear flow physics and offers an early and improved understanding of air vehicle aerodynamics and stability and control characteristics. This Special Issue covers recent computational efforts on simulation of aerospace vehicles including fighter aircraft, rotorcraft, propeller driven vehicles, unmanned vehicle, projectiles, and air drop configurations. The complex flow physics of these configurations pose significant challenges in CFD modeling. Some of these challenges include prediction of vortical flows and shock waves, rapid maneuvering aircraft with fast moving control surfaces, and interactions between propellers and wing, fluid and structure, boundary layer and shock waves. Additional topic of interest in this Special Issue is the use of CFD tools in aircraft design and flight mechanics. The problem with these applications is the computational cost involved, particularly if this is viewed as a brute-force calculation of vehicle’s aerodynamics through its flight envelope. To make progress in routinely using of CFD in aircraft design, methods based on sampling, model updating and system identification should be considered.
Author: Nandan K. Sinha
Publisher: CRC Press
ISBN: 1498746063
Category : Science
Languages : en
Pages : 348
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Book Description
Advanced Flight Dynamics aim to integrate the subjects of aircraft performance, trim and stability/control in a seamless manner. Advanced Flight Dynamics highlights three key and unique viewpoints. Firstly, it follows the revised and corrected aerodynamic modeling presented previously in recent textbook on Elementary Flight Dynamics. Secondly, it uses bifurcation and continuation theory, especially the Extended Bifurcation Analysis (EBA) procedure devised by the authors, to blend the subjects of aircraft performance, trim and stability, and flight control into a unified whole. Thirdly, rather than select one control design tool or another, it uses the generalized Nonlinear Dynamic Inversion (NDI) methodology to illustrate the fundamental principles of flight control. Advanced Flight Dynamics covers all the standard airplane maneuvers, various types of instabilities normally encountered in flight dynamics and illustrates them with real-life airplane data and examples, thus bridging the gap between the teaching of flight dynamics/ control theory in the university and its practice in airplane design bureaus. The expected reader group for this book would ideally be senior undergraduate and graduate students, practicing aerospace/flight simulation engineers/scientists from industry as well as researchers in various organizations. Key Features: Focus on unified nonlinear approach, with nonlinear analysis tools. Provides an up-to-date, corrected, and unified presentation of aircraft trim, stability and control analysis including nonlinear phenomena and closed-loop stability analysis. Contains a computational tool and real-life example carried through the chapters. Includes complementary nonlinear dynamic inversion control approach, with relevant aircraft examples. Fills the gap in the market for a text including non-linear flight dynamics and continuation methods.
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722379582
Category :
Languages : en
Pages : 28
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Book Description
A short theoretical study of aircraft aerodynamic model equations with unsteady effects is presented. The aerodynamic forces and moments are expressed in terms of indicial functions or internal state variables. The first representation leads to aircraft integro-differential equations of motion; the second preserves the state-space form of the model equations. The formulations of unsteady aerodynamics is applied in two examples. The first example deals with a one-degree-of-freedom harmonic motion about one of the aircraft body axes. In the second example, the equations for longitudinal short-period motion are developed. In these examples, only linear aerodynamic terms are considered. The indicial functions are postulated as simple exponentials and the internal state variables are governed by linear, time-invariant, first-order differential equations. It is shown that both approaches to the modeling of unsteady aerodynamics lead to identical models. Klein, Vladislav and Noderer, Keith D. Langley Research Center RTOP 505-64-52-01...
Author: Nandan K. Sinha
Publisher: CRC Press
ISBN: 1000441903
Category : Science
Languages : en
Pages : 389
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Book Description
Elementary Flight Dynamics with an Introduction to Bifurcation and Continuation Methods, Second Edition is aimed at senior undergraduate and graduate students of aerospace and mechanical engineering. The book uses an optimal mix of physical insight and mathematical presentation to illustrate the core concepts of professional aircraft flight dynamics. An updated version of the aerodynamic model is presented with the corrected definition of rate (dynamic) derivatives, supported with examples of real-life airplanes and related data and by open-source computational tools. It introduces bifurcation and continuation methods as a tool for flight dynamic analysis. FEATURES Covers an up-to-date, corrected, ‘clean’ presentation of the elements of flight dynamics Presents a blend of theory, practice and application with real-life practical examples Provides a unique viewpoint of applied aerodynamicists and aircraft designers Introduces bifurcation and continuation methods as a tool for flight dynamics analysis Includes a computational tool with real-life examples carried throughout the chapters The book is enriched with case studies of flight dynamics of a bird’s flight, of a six-seater rigid-wing airplane from a design perspective, and airship dynamics to highlight the modal behaviour of similar-looking vehicles that are distinct from each other. Excerpts from reviews of the first edition: "Flight dynamics is a topic that can cause difficulties to aerospace engineering students. This text leads the reader gently through the material with plenty of practical examples and student exercises. As such, it is easy to follow the material and to gradually develop a deep understanding of a demanding topic. The book is ideal for undergraduate students and is a good text for graduate students."––James F. Whidborne, Cranfield University, United Kingdom "The book covers all the aspects of flight dynamics traditionally found in such texts interspersed with examples of the treatment of features of current air vehicles....In my opinion, this book covers the subject comprehensively and is a desirable reference source for undergraduates and graduates alike."––R.J. Poole, MRAeS, The Aeronautical Journal, June 2014 "The book design and the methodology of interpretation are directed to a wide range of target audience/population interested in studying the dynamics of flight. Given the scale and organization of information, the book will also be a useful tool in the analysis of flight dynamics for professionals in this field. The book is sure to appeal to anyone interested in the dynamics of flight."––Jaroslav Salga, Advances in Military Technology, June 2014
Author: Konstantin Volkov
Publisher: BoD – Books on Demand
ISBN: 9535138073
Category : Technology & Engineering
Languages : en
Pages : 242
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Book Description
The book focuses on the synthesis of the fundamental disciplines and practical applications involved in the investigation, description, and analysis of aircraft flight including applied aerodynamics, aircraft propulsion, flight performance, stability, and control. The book covers the aerodynamic models that describe the forces and moments on maneuvering aircraft and provides an overview of the concepts and methods used in flight dynamics. Computational methods are widely used by the practicing aerodynamicist, and the book covers computational fluid dynamics techniques used to improve understanding of the physical models that underlie computational methods.
Author: Jitendra R. Raol
Publisher: CRC Press
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 442
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Book Description
Using a systems approach to illustrate key topics, this book reviews the basics of aerodynamics and control theory, applying these concepts to the real-world design, testing, and analysis of flight systems.
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722379902
Category :
Languages : en
Pages : 44
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Book Description
Aerodynamic equations with unsteady effects were formulated for an aircraft in one-degree-of-freedom, small-amplitude, harmonic motion. These equations were used as a model for aerodynamic parameter estimation from wind tunnel oscillatory data. The estimation algorithm was based on nonlinear least squares and was applied in three examples to the oscillatory data in pitch and roll of 70 deg triangular wing and an X-31 model, and in-sideslip oscillatory data of the High Incidence Research Model 2 (HIRM 2). All three examples indicated that a model using a simple indicial function can explain unsteady effects observed in measured data. The accuracy of the estimated parameters and model verification were strongly influenced by the number of data points with respect to the number of unknown parameters. Klein, Vladislav and Noderer, Keith D. Langley Research Center RTOP 505-64-52-01...
Author: Clotaire Wood
Publisher:
ISBN:
Category : Air flow
Languages : en
Pages : 28
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Book Description
Summary: Flight tests were made at high speeds with a P-47D airplane to determine the flow characteristics, as indicated by wool tufts, on a section of the upper surface of the wing. The behavior of the tufts, which were distributed over a section of the wing from 39.5 to 52.5 percent semispan, was determined from motion pictures. The tests were made in straight flight and in turns under conditions in which airplane lift coefficients from 0.10 to 0.54 and airplane Mach numbers from 0.58 to 0.78 were obtained. The results of the tests indicated that the flow remained smooth over the test panel until the critical Mach number of the panel was exceeded by 0.08 at a lift coefficient of 0.10 and by 0.05 at a lift coefficient of 0.50. Beyond these Mach numbers, the tufts indicated unsteadiness of flow and, finally, local separation when the Mach number exceeded the critical value by 0.13 at a lift coefficient of 0.10 and by 0.10 at a lift coefficient of 0.50. The region of separated flow originated in the neighborhood of 30 percent chord at high lift coefficients and 45 percent chord at low lift coefficients. Separation appeared to extend over not more than 15 percent chord.
