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Author: Heinz Fuchs Publisher: ISBN: Category : Languages : en Pages : 19
Book Description
The prediction methodology of dynamic derivatives is presented as derived from semiempirical calculation procedures like 'USAF Stability and Control Datcom' in combination with some modifications necessary for tactical missile configurations at higher angles-of-attack. The main subject is the longitudinal stability derivatives and the roll damping derivativum. A comparison of theoretical and experimental results is presented where different dynamic wind tunnel test equipments are explained including the data evaluation theory. Some aspects of modification of the present linear data evaluation method to nonlinear terms at high angles-of-attack are shown with an example of a fighter aircraft configuration using the MOD test rig in the Dornier wind tunnel. Guided missiles, Aerodynamics. (JES).
Author: Heinz Fuchs Publisher: ISBN: Category : Languages : en Pages : 19
Book Description
The prediction methodology of dynamic derivatives is presented as derived from semiempirical calculation procedures like 'USAF Stability and Control Datcom' in combination with some modifications necessary for tactical missile configurations at higher angles-of-attack. The main subject is the longitudinal stability derivatives and the roll damping derivativum. A comparison of theoretical and experimental results is presented where different dynamic wind tunnel test equipments are explained including the data evaluation theory. Some aspects of modification of the present linear data evaluation method to nonlinear terms at high angles-of-attack are shown with an example of a fighter aircraft configuration using the MOD test rig in the Dornier wind tunnel. Guided missiles, Aerodynamics. (JES).
Author: James DeSpirito Publisher: ISBN: Category : Computational fluid dynamics Languages : en Pages : 0
Book Description
The prediction of the dynamic stability derivatives-roll-damping, Magnus, and pitch-damping moments-were evaluated for three spin-stabilized projectiles using steady-state computational fluid dynamic (CFD) calculations. Roll-damping CFD predictions were found to be very good across the Mach number range investigated. Magnus moment predictions were very good in the supersonic flight regime; however, the accuracy varied in the subsonic and transonic flight regime. The best Magnus moment prediction in the subsonic flight regime was for the square-base projectile that did not exhibit highly nonlinear Magnus moments. A primary contribution of this report is the demonstration that the pitch-damping moment can be adequately predicted via steady-state methods rather than resorting to unsteady techniques. The predicted pitch-damping moment compared very well to experimental data for the three projectiles investigated. For one configuration, the pitch-damping moment was predicted by several CFD codes, two different steady-state methods, and a time-accurate planar pitching motion method. All methods compared very well to each other and to the experimental data.
Author: Andrea Da Ronch Publisher: ISBN: Category : Languages : en Pages :
Book Description
In this thesis, the exploitation of computational fluid dynamics (CFD) methods for the flight dynamics of manoeuvring aircraft is investigated. It is demonstrated that CFD can now be used in a reasonably routine fashion to generate stability and control databases. Different strategies to create CFD-derived simulation models across the flight envelope are explored, ranging from combined low-fidelity/high-fidelity methods to reduced-order modelling. For the representation of the unsteady aerodynamic loads, a model based on aerodynamic derivatives is considered. Static contributions are obtained from steady-state CFD calculations in a routine manner. To more fully account for the aircraft motion, dynamic derivatives are used to update the steady-state predictions with additional contributions. These terms are extracted from small-amplitude oscillatory tests. The numerical simulation of the flow around a moving airframe for the prediction of dynamic derivatives is a computationally expensive task. Results presented are in good agreement with available experimental data for complex geometries. A generic fighter configuration and a transonic cruiser wind tunnel model are the test cases. In the presence of aerodynamic non-linearities, dynamic derivatives exhibit significant dependency on flow and motion parameters, which cannot be reconciled with the model formulation. An approach to evaluate the sensitivity of the non-linear flight simulation model to variations in dynamic derivatives is described. The use of reduced models, based on the manipulation of the full-order model to reduce the cost of calculations, is discussed for the fast prediction of dynamic derivatives. A linearized solution of the unsteady problem, with an attendant loss of generality, is inadequate for studies of flight dynamics because the aircraft may experience large excursions from the reference point. The harmonic balance technique, which approximates the flow solution in a Fourier series sense, retains a more general validity. The model truncation, resolving only a small subset of frequencies typically restricted to include one Fourier mode at the frequency at which dynamic derivatives are desired, provides accurate predictions over a range of two- and three-dimensional test cases. While retaining the high fidelity of the full-order model, the cost of calculations is a fraction of the cost for solving the original unsteady problem. An important consideration is the limitation of the conventional model based on aerodynamic derivatives when applied to conditions of practical interest (transonic speeds and high angles of attack). There is a definite need for models with more realism to be used in flight dynamics. To address this demand, various reduced models based on system-identification methods are investigated for a model case. A non-linear model based on aerodynamic derivatives, a multi-input discrete-time Volterra model, a surrogate-based recurrence-framework model, linear indicial functions and radial basis functions trained with neural networks are evaluated. For the flow conditions considered, predictions based on the conventional model are the least accurate. While requiring similar computational resources, improved predictions are achieved using the alternative models investigated. Furthermore, an approach for the automatic generation of aerodynamic tables using CFD is described. To efficiently reduce the number of high-fidelity (physics-based) analyses required, a kriging-based surrogate model is used. The framework is applied to a variety of test cases, and it is illustrated that the approach proposed can handle changes in aircraft geometry. The aerodynamic tables can also be used in real-time to fly the aircraft through the database. This is representative of the role played by CFD simulations and the potential impact that high-fidelity analyses might have to reduce overall costs and design cycle time.
Author: Wolfgang Nitsche Publisher: Springer Science & Business Media ISBN: 3663109011 Category : Mathematics Languages : en Pages : 550
Book Description
This volume contains the papers of the 11th Symposium of the AG STAB (German Aerospace Aerodynamics Association). In this association those scientists and engineers from universities, research-establishments and industry are involved, who are doing research and project work in numerical and experimental fluid mechanics and aerodynamics for aerospace and other applications. Many of the contributions are giving results from the "Luftfahrtforschungsprogramm der Bundesregierung (German Aeronautical Research Programme). Some of the papers report on work sponsored by the Deutsche Forschungsgemeinschaft, DFG, which also was presented at the symposium. The volume gives a broad overview over the ongoing work in this field in Germany.
Author: Maosen Cao Publisher: World Scientific ISBN: 9813145617 Category : Technology & Engineering Languages : en Pages : 1398
Book Description
This proceedings consists of 162 selected papers presented at the 2nd Annual International Conference on Mechanics and Mechanical Engineering (MME2015), which was successfully held in Chengdu, China between December 25-27, 2015.MME2015 is one of the key international conferences in the fields of mechanics, mechanical engineering. It offers a great opportunity to bring together researchers and scholars around the globe to deliver the latest innovative research and the most recent developments in the field of Mechanics and Mechanical Engineering.MME2015 received over 400 submissions from about 600 laboratories, colleges and famous institutes. All the submissions have undergone double blind reviewed to assure the quality, reliability and validity of the results presented. These papers are arranged into 6 main chapters according to their research fields. These are: 1) Applied Mechanics 2) Mechanical Engineering and Manufacturing Technology 3) Material Science and Material Engineering 4) Automation and Control Engineering 5) Electrical Engineering 6) System Modelling and Simulation.This proceedings will be invaluable to academics and professionals interested in Mechanics and Mechanical Engineering.
Author: Peter T. Wooler Publisher: ISBN: Category : Mathematical models Languages : en Pages : 504
Book Description
Volume 2. Application of Prediction Methods. Final rept. 1 May 69-31 Jan 1972, FWooler, Peter T. ;Kao, Hsiao C. ;Schwendemann, Myles F. ;Wasson, Howard R. ;Ziegler, Henry ;NOR-72-9-Vol-2F33615-69-C-1602AF-698BTAFFDLTR-72-26- Vol-2See also Volume 1, AD752557 and Volume 3, AD752559.(*aerodynamic characteristics, mathematical prediction), (*short takeoff aircraft, aerodynamic characteristics), vertical takeoff aircraft, flow fields, lift, predictions, flow separation, vortices, wake, stalling, interactions, mathematical models, mapping(transformations)computer aided analysis, computer aided design, design criteriaAnalytical engineering methods are developed for use in predicting the static and dynamic stability and control derivatives and force and moment coefficients of lift-jet, lift-fan, and vectored thrust V/STOL aircraft in the hover and transition flight regimes. The aircraft configurations studied have a conventional wing, fuselage and empennage. The prediction methods are applied to a number of V/STOL configurations in this volume.
Author: Heinz Fuchs
Author: Heinz Fuchs
Author: L. Landweber
Author: 
Author: James DeSpirito
Author: Andrea Da Ronch
Author: Wolfgang Nitsche
Author: S. B. Taylor
Author: Maosen Cao
Author: 
Author: Peter T. Wooler