Download or read book Modelling and Simulation of Gust and Atmospheric Turbulence Effects on Flexible Aircraft Flight Dynamics written by Pau Castells Marin and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The prediction of the aircraft response to gust and turbulence is of major importance for different purposes. Gust load analysis is an essential part of aircraft design and certification. The effect of gust and turbulence on aircraft flight dynamics is also of interest. Models able to capture relevant effects at these conditions in early design phases are essential in order to anticipate and assess the aircraft response and flight control laws in realistic atmospheric disturbances before flight test. This work proposes a modelling strategy to capture relevant physics when simulating the aircraft response to gust and turbulence for flight dynamics investigations. The model provides accuracy at a low computational cost as well as consistency with gust loads analysis enabling multidisciplinary design. The approach is based on the integration of a nonlinear quasi-steady flexible flight dynamics model with an unsteady aeroelastic model linearized around a nonlinear steady state. The gust-induced forces have a significant impact on aircraft flight dynamics. Low computing times are required to cover several flight conditions and aircraft parameters. A computationally efficient multipoint aerodynamic model, which captures both unsteady aerodynamic and gust propagation effects, is generated from linearized Computational Fluid Dynamics (CFD) simulations in the frequency domain. The model is identified through a rational function approximation allowing for time domain simulations. A reduced number of additional aerodynamic states is sufficient to capture the main effects at low frequencies for flight dynamics analysis. The impact of dynamic flexibility on the response is also evaluated. Only the most energetic flexible modes are retained to reduce the number of states and ensure a low computation time. The approach is applied to simulate the vertical and lateral response of a passenger aircraft to theoretical disturbance profiles as well as realistic atmospheric turbulence at different flight conditions. Aerodynamic nonlinear effects, such as local stalls due to shock motion, in transonic conditions may appear. The linearized model is able to capture the global aircraft response at these conditions with low amplitude shock motions. Results are compared and validated with a CFD simulation based approach, coupled with a structural dynamics and flight mechanics solver. Measures from flight test are also used to assess the modelling approach. The effect of uncertainties on the response is analysed, in terms of the turbulence variation along the wingspan. Simulation results show that relevant aerodynamic effects due to gust and turbulence are captured in the frequency range of interest for flight dynamics investigations.
Download or read book The Flight of Flexible Aircraft in Turbulence State of the Art in the Description and Modelling of Atmospheric Turbulence Meeting of the Structures and Materials Panel of AGARD 64th Held in Athens Greece on 28 September 3 October 1986 written by ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRAN CE) and published by . This book was released on 1987 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: A brief review is made of where we stand presently with respect to our understanding of aircraft encounter of atmospheric turbulence, both from the point of view of describing or modeling the turbulence and with respect to our ability to calculate the resulting airplane loads. Some of the more recent studies of gust measurements and of reducing airline gust response data are discussed. Special attention is given to gust analysis requirements as involved in airplane certification and whether there is a need for additional or different requirements. The paper concludes with the review of a recent study in which amazingly simple and universal gust response equations were discovered; the possible impact of these new findings on future work is indicated.
Download or read book Atmospheric Turbulence Simulation Techniques with Application to Flight Analysis written by Show-Tien Wang and published by . This book was released on 1980 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Statistical modeling of atmospheric turbulence is discussed. The statistical properties of atmospheric turbulence, in particular the probability distribution, the spectra, and the coherence are reviewed. Different atmospheric turbulence simulation models are investigated, and appropriate statistical analyses are carried out to verify their validity. The models for simulation are incorporated into a computer model of aircraft flight dynamics. Statistical results of computer simulated landings for an aircraft having characteristics of a DC-8 are reported for the different turbulence simulation techniques. The significance of various degrees of sophistication in the turbulence simulation techniques on the landing performance of the aircraft is discussed.
Download or read book The Effects of Atmospheric Turbulence Upon Flight at Low Altitude and High Speed written by Charles Boris Notess and published by . This book was released on 1961 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of On line Simulation of the Flight Dynamics of a Flexible Aircraft in Turbulence written by G.A.J. van de Moesdijk and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gust Loading of Rigid and Flexible Aircraft in Continuous Atmospheric Turbulence written by Kenneth A. Foss and published by . This book was released on 1958 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Effects of High altitude Turbulence Encounters on the XB 70 Airplane written by Ronald J. Wilson and published by . This book was released on 1971 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: A turbulence response investigation was conducted with the XB-70 airplane. No special turbulence penetration techniques, speeds, or other restrictions were specified for the investigation, nor were any flights made solely to obtain turbulence data. During 79 flights, turbulence was encountered, and recorded on a VGH recorder, 6.2 percent of the total flight distance at supersonic speeds above an altitude of 12,192 meters (40,000 feet). Geographical locations are given for selected turbulence encounters. For 22 flights the airplane was instrumented to measure true gust velocities and the structural acceleration response to turbulence. The turbulence intensities measured were very low in comparison with those measured at high altitudes in other investigations. Acceleration response spectra, frequency response transfer functions, and coherence functions were computed from three turbulence encounters at Mach numbers of 0.88, 1. 59, and 2.35. Results are compared with calculated studies. Frequencies from the vertical and lateral structural modes, dominant in the airplane acceleration responses, were compared with the natural frequencies of the human body in the vertical and lateral directions.
Download or read book Categorization of Atmospheric Turbulence in Terms of Aircraft Response for Use in Turbulence Reports and Forecasts written by Elijah W. Turner and published by . This book was released on 1981 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Survey on Effect of Surface Winds on Aircraft Design and Operation and Recommendations for Needed Wind Research written by John C. Houbolt and published by . This book was released on 1973 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Non gaussian Turbulence Simulation written by Paul M. Reeves and published by . This book was released on 1969 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comparison of the statistical properties of low altitude atmospheric turbulence and the characteristics of presently used simulation techniques shows that these techniques do not satisfactorily account for the non-Gaussian nature of turbulence. A non-Gaussian turbulence simulation, intended to be used in conjunction with piloted flight simulators, is developed. The simulation produces three simultaneous random processes which represent the three orthogonal gust components. The probability distribution of each component is characterized by a modified Bessel function. The rms intensity and scale length of each component are independent parameters. A general method of introducing cross spectra between components is demonstrated. The multiplication of independent random processes is used to generate each of the gust components. Gaussian white noise generators, analog multipliers, and linear filters are used throughout the simulation. A complete analog circuit diagram is presented. (Author).
Download or read book The Flight of Flexible Aircraft in Turbulence State of the Art in the Description and Modelling of Atmospheric Turbulence Addendum written by and published by . This book was released on 1988 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-scale use of flight recorders by commercial airlines, coupled with the enhanced quality of results offered by modern computer-based reduction processes makes it possible to broaden knowledge of the phenomenon of atmospheric turbulence. At the same time, new methods for predicting the response of flexible aircraft to turbulence are being proposed, and novel gust alleviation systems are being designed and tested. The Structures and Materials Panel held two Workshops on this topic. This volume records the presentations made at the second workshop to discuss methods of analysis and regulations. Papers include: Current and proposed gust criteria and analysis methods - An FAA overview; Flight test equipment for the on-board measurement of wind and turbulence; Matching P.S.D. - design loads; Summary of methods for establishing airframe design loads from continuous gust design criteria; Comparison of the influence of different gust models on structural design; Measured and predicted responses of the NORD 260 aircraft to low altitude atmospheric turbulence; Review of measured gust responses in the light of modern analysis methods. Keywords: Flight characteristics; Data reduction airborne accelerometers. (EDC).
Download or read book Introduction to Aircraft Flight Mechanics written by Thomas R. Yechout and published by AIAA. This book was released on 2003 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on a 15-year successful approach to teaching aircraft flight mechanics at the US Air Force Academy, this text explains the concepts and derivations of equations for aircraft flight mechanics. It covers aircraft performance, static stability, aircraft dynamics stability and feedback control.
Download or read book High Performance Computing in Science and Engineering 22 written by Wolfgang E. Nagel and published by Springer Nature. This book was released on with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gust Loads on Aircraft written by Frederic M. Hoblit and published by AIAA. This book was released on 1988 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamic Response of Airplanes to Atmospheric Turbulence Including Flight Data on Input and Response written by John C. Houbolt and published by . This book was released on 1964 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: A coordinated account of flight measurements of random atmospheric turbulence, of calculated and experimentally determined airplane transfer functions, and of analytical procedures for determining output responses is given based on power spectral techniques. Implications of these techniques for load prediction and for design are discussed, and brief review of basic procedures and mathematics involved is also included.
Download or read book Flight Stability and Automatic Control written by Robert C. Nelson and published by WCB/McGraw-Hill. This book was released on 1998 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Flight Stability and Automatic Control presents an organized introduction to the useful and relevant topics necessary for a flight stability and controls course. Not only is this text presented at the appropriate mathematical level, it also features standard terminology and nomenclature, along with expanded coverage of classical control theory, autopilot designs, and modern control theory. Through the use of extensive examples, problems, and historical notes, author Robert Nelson develops a concise and vital text for aircraft flight stability and control or flight dynamics courses.
Download or read book Airplane Flying Characteristics in Turbulence written by E. D. Onstott and published by . This book was released on 1971 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method for predicting the performance of the total pilot-vehicle system has been developed for the lateral dynamics of Class 4 airplanes. This method, which is based on pilot model theory and multiloop analysis, predicts tracking errors for command tracking tasks and also for attitude hold tracking tasks in turbulence. The predictions are in terms of root mean square time domain statistics and are obtained by means of a fully automated multiloop analysis performance prediction program available from the United States Air Force. Thus, system performance can be evaluated analytically in terms of familiar time domain root mean square statistics. The validity and accuracy of this method have been ascertained by means of moving base simulation on the Northrop Large-Amplitude Flight Simulator operating in five-degree-of-freedom motion.
