A two-dimensional aerodynamics representation analysis is introduced for the investigation of inviscid flowfields of unsteady airfoils. The problem of the unsteady flow of a two-dimensional NACA airfoil is therefore reduced to the solution of a non-linear multidimensional singular integral equation, when the form of the source and vortex strength distribution is dependent on the history of the above distribution on the NACA airfoil surface. An application is given to the determination of the velocity and pressure coefficient field around an aircraft by assuming constant source distribution. 相似文献
Real-time infrared radiation simulation technology can provide effective support for rapid design and evaluation of a system which integrates infrared imaging technology. Considering the aerodynamic heating effect, this paper presents a real-time infrared radiation characteristic simulation method of aircraft skin based on the panel element method, which can help to assess the infrared radiation impacts of different environment factors and materials. A 3-D model of an aircraft was established and its surface was divided into different parts and panel element meshes to attach material properties. For each mesh, its heat exchange equation is solved so as to obtain the whole skin’s temperature and infrared radiation distribution. The simulation results reveal the influence of different factors on the skin surface radiation, including environmental radiation, aerodynamic heating and material properties. And the credibility and efficiency of the proposed aerodynamic heating simulation method were confirmed by comparing to the CFD simulation results. 相似文献
The standard method for computing noise contours around civil airports is SAE-AIR-1845 (FAA Integrated Noise Model, European ECAC-CEAC Doc. 29). It is subject to the inaccuracies implicit in the model as well as those caused by erroneous or imprecise input data. Regarding the latter, the existing errors and/or uncertainties, may be amplified in the output results, to a greater or lower extent, in some cases offering unreliable predictions.In order to study this phenomenon, the Institute of Sound and Vibration Research (ISVR - Southampton) carried out a theoretical sensitivity analysis based on the segmentation technique, regarding the input parameters of the SAE-AIR-1845, and obtaining the input variables of the model, the variation of which implied greater changes in the output variables. The results were validated by using the FAA Integrated Noise Model Version 6.0 software, based on the aforementioned document. It has been revealed that the model has a greater sensitivity to factors that modify the flight path, and a lower sensitivity to the other parameters. Thus, an error greater than 10% in the variable “gross weight” offers an additional error of between 3 and 7 dB. However, parameters such as the ID of the flaps hardly modify the results obtained for the least favourable case by 1 dB.As a result of this research, the sensitivity of the model was quantified for each of the input parameters (taken alone and also in interaction with other parameters), and criteria for the minimisation of global error, resulting from uncertainties in the input parameters, were stated. 相似文献
Given a schedule of flights to be flown, the aircraft fleeting and routing problem (AFRP) consists of determining a minimum-cost route assignment for each aircraft so as to cover each flight by exactly one aircraft while satisfying maintenance requirements and other activity constraints. We investigate network flow-based heuristic approaches for this problem. Computational experiments conducted on real-data given by TunisAir show that the proposed heuristic consistently yields very near-optimal solutions while requiring modest CPU effort. 相似文献
In the fractional ownership model, the partial owner of an aircraft is entitled to certain flight hours per year, and the management company is responsible for all the operational considerations of the aircraft and for making an aircraft available to the owner at the requested time and place. In the recent years although the industry as a whole has experienced significant growth, most of the major fractional jet management companies have been unprofitable. To increase profitability a management company must minimize its operating costs and increase its crew and aircraft utilization. In this paper, we present a methodology for efficiently scheduling the available resources of a fractional jet management company that takes into consideration the details in real world situations. We then discuss several strategic planning issues, including aircraft maintenance, crew swapping, demand increase and differentiation, and analyze their effects on the resource utilization and profitability. 相似文献
Air transportation is one of the most important services in the world, contributing greatly to the advancement of modern society. However, it has a local and a global impact on the environment making aircraft take-off noise an important environmental public health concern near airports, and this is a significant subject for monitoring and research. In this work an experimentally validated computational model for aircraft classification is presented. In addition, potentially harmful effects to human health and comfort associated with noise exposure are discussed. The feature extraction of aircraft take-off signals is conducted through a 1/24 octave analysis and Mel frequency cepstral coefficients (MFCC). The aircraft classification is made by using two parallel feed forward neural networks. The aircraft are clustered into classes depending on the installed engine type. This model has 13 aircraft classes and a classification level above 83% with measurements in real time environment. 相似文献
This paper presents a systems viewpoint for developing an advanced decision support system for aircraft safety inspectors. Research results from a Federal Aviation Administration (FAA) sponsored project to use neural network and expert systems technology to analyze aircraft maintenance databases are summarized. One of the main objectives of this research is to define more refined “alert” indicators for national comparison purposes that can signal potential problem areas by aircraft type for safety inspector consideration.
Integration aspects are addressed on two levels: (1) integration of the various technical components of the decision support system, and (2) integration of the decision support system with individual behavior, management systems and organizational structure, as well as corporate culture across both formal and informal dimensions. The paper summarizes the creation of strategic “inspection profiles” for aging aircraft and reliability curve fitting for structural components both based upon using neural network technology. Also, the potential use of a model-based expert system to facilitate field inspection diagnostics is presented. Finally, a framework for developing an intelligent decision system to support aircraft safety inspections is proposed that links expert systems, neural networks, as well as a paradigm of the decision making process typically used in unstructured situations. 相似文献
This research has developed a systematic aircraft noise charge scheme, based on noise social costs, with a view to its application in Taiwan. The paper starts with a brief review of current structures and applications of noise charges, a market-based measure, in mitigating aircraft noise worldwide. The evaluation of aircraft noise social cost is an attempt at putting noise nuisance into monetary terms. The total and average noise social cost per flight at one airport is clearly different from another, depending mainly on the size of the noise contour and the number of residents affected. This research estimates the average noise social costs at various airports, using nine Taiwanese airports as case studies. Depending on the marginal impact of a flight and the mixture of aircraft types at each airport, the noise social cost per landing and take-off is then estimated for different aircraft types. The results of this study can inform airport, airline and local administration policies for taking environmental concerns into account when setting up noise charges, revising noise insulation schemes, and developing strategies for airport expansion and airline operations. 相似文献