Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 6 Articles
Thesimulated training is an important issue for any type of missions such as aerial, ground, sea, or even space missions. In this paper,\na new flexible aerial simulator based on active hybrid architecture is introduced.The simulator infrastructure is applicable to any\ntype of training missions and research activities. This software-based simulator is tested on aerial missions to prove its applicability\nwithin time critical systems.Theproposed active hybrid architecture is introduced via using the VB.NET andMATLAB in the same\nsimulation loop. It exploits the remarkable computational power ofMATLAB as a backbone aircraftmodel, and suchmathematical\nmodel provides realistic dynamics to the trainee. Meanwhile, the Human-Machine Interface (HMI), the mission planning, the\nhardware interfacing, data logging, and MATLAB interfacing are developed using VB.NET. The proposed simulator is flexible\nenough to performnavigation and obstacle avoidance training missions.The active hybrid architecture is used during the simulated\ntraining, and also through postmission activities (like the generation of signals playback reports for evaluation purposes). The\nresults show the ability of the proposed architecture to fulfill the aerial simulator demands and to provide a flexible infrastructure\nfor different simulated mission requirements. Finally, a comparison with some existing simulators is introduced....
Hypersonic waveriders have a large flight envelope, leading to the difficulty in keeping overall flight stability for a fixed geometry.\nAccordingly, hypersonic waveriders can be considered to design as a morphing vehicle such that the flight range is expanded\nfor waveriding stability. To this end, this paper investigates the collaborative deformation design using control integrated analysis\nmethods for the hypersonic waverider. Firstly, a parametricmodel is applied to combine the shape deformationwith the geometrical\nproperties. Secondly, the morphing process with regard to the change in a single geometric parameter and the static and dynamic\ncharacteristics affected by this deformation are analyzed. Afterwards, the collaborative relations are discussed for the changes in the\nlower forebody angle and elevon area. Furthermore, a flight control law is designed to guarantee flight stability while implementing\nthe collaborative deformation, and the morphing results are evaluated based on the control-oriented idea. Finally, a simulation\nexample is used to verify the effectiveness of the proposed methods for the hypersonic waverider....
The hybrid vortex method, in which vortex panel method is combined with the viscous-vortex particle method (HPVP), was\nestablished to model the wind turbine aerodynamic and relevant numerical procedure program was developed to solve flow\nequations. The panel method was used to calculate the blade surface vortex sheets and the vortex particle method was employed to\nsimulate the blade wake vortices. As a result of numerical calculations on the flow over a wind turbine, the HPVP method shows\nsignificant advantages in accuracy and less computation resource consuming.Thevalidation of the aerodynamic parameters against\nPhase VI wind turbine experimental data is performed, which shows reasonable agreement....
Diffusion-bonded titanium hollow warren structures have been successfully applied in aircraft engine components, such as fan\nblade, and OGV, while the optimal design of the hollow warren structure to improve its impact resistance, especially under birdstrike\nevent, has been a challenge. In this work, a series of impact tests and numerical simulations are carried out to investigate\nthe effect of key geometric features on the overall impact strength of a panel-shaped titanium hollow warren structure. Based on\nexperimental and numerical studies, a quantitative relationship between diffusion bonding seam strength and the overall impact\nstrength is developed.Meanwhile, key geometric factors affecting the resultant bonding seam strength for a typical manufacturing\nprocess are identified. This work provides useful references for the optimal design to increase impact resistance for aircraft engine\nhollow warren structure components....
Reignition phenomena occurring in a supersonic nozzle flow may present a crucial safety issue for rocket propulsion systems.\nThese phenomena concern mainly rocket engines which use H2 gas (GH2) in the film cooling device, particularly when the nozzle\noperates under over expanded flow conditions at sea level or at low altitudes. Consequently, the induced wall thermal loads can\nlead to the nozzle geometry alteration, which in turn, leads to the appearance of strong side loads that may be detrimental to the\nrocket engine structural integrity. It is therefore necessary to understand both aerodynamic and chemical mechanisms that are\nat the origin of these processes. This paper is a numerical contribution which reports results from CFD analysis carried out for\nsupersonic reactive flows in a planar nozzle cooled with GH2 film. Like the experimental observations, CFD simulations showed\ntheir ability to highlight these phenomena for the same nozzle flow conditions. Induced thermal load are also analyzed in terms\nof cooling efficiency and the results already give an idea on their magnitude. It was also shown that slightly increasing the film\ninjection pressure can avoid the reignition phenomena by moving the separation shock towards the nozzle exit section....
This paper presents a novel robust attack angle control approach, which can effectively suppress the impacts from system\nuncertainties and servo-loop dynamics.Asecond-order linear model of electromechanical servo loop is considered in themodeling\nand design processes. With regard to the block-structure models facing attack angle control, the multiple robust surfaces and\ndynamic surface control (DSC) approaches are both employed. By means of Lyapunov function method, the stability conditions of\nattack angle control systems are, respectively, given without/with considering the servo-loop dynamics in design process. Computer\nsimulation results present that, compared with the attack angle control scheme which does not consider the servo-loop dynamics in\ndesign process, the proposed scheme can guarantee that the whole attack angle control system possesses the better comprehensive\nperformances. Moreover, it is easy to be realized in engineering application....
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