Journal of Aeronautics and Aerospace Engineering最新文献

{"title":"Implementing Conditional Inequality Constraints for Optimal Collision Avoidance","authors":"N. E. Smith, Christopher D. Arendt, R. Cobb, Jonah A. Reeger","doi":"10.4172/2168-9792.1000195","DOIUrl":"https://doi.org/10.4172/2168-9792.1000195","url":null,"abstract":"Current Federal Aviation Administration regulations require that passing aircraft must either meet a specified horizontal or vertical separation distance. However, solving for optimal avoidance trajectories with conditional inequality path constraints is problematic for gradient-based numerical nonlinear programming solvers since conditional constraints typically possess non-differentiable points. Further, the literature is silent on robust treatment of approximation methods to implement conditional inequality path constraints for gradient-based numerical nonlinear programming solvers. This paper proposes two efficient methods to enforce conditional inequality path constraints in the optimal control problem formulation and compares and contrasts these approaches on representative airborne avoidance scenarios. The first approach is based on a minimum area enclosing superellipse function and the second is based on use of sigmoid functions. These proposed methods are not only robust, but also conservative, that is, their construction is such that the approximate feasible region is a subset of the true feasible region. Further, these methods admit analytically derived bounds for the over-estimation of the infeasible region with a demonstrated maximum error of no greater than 0.3% using the superellipse method, which is less than the resolution of typical sensors used to calculate aircraft position or altitude. However, the superellipse method is not practical in all cases to enforce conditional inequality path constraints that may arise in the nonlinear airborne collision avoidance problem. Therefore, this paper also highlights by example when the use of sigmoid functions are more appropriate.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132073386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aeroacousticâs Investigation on High-Lift Device by using a ModernHybrid RANS/LES-Model","authors":"M. Schneider","doi":"10.4172/2168-9792.1000194","DOIUrl":"https://doi.org/10.4172/2168-9792.1000194","url":null,"abstract":"This study focuses on the development, validation and application of the interdisciplinary computational fluid dynamics/computational aeroacoustics (CFD/CAA) method with the name Flight-Physics Simulator AEOLus (FPSAEOLus). FPS-AEOLus is based on enhanced conservative, anisotropic, hybrid Reynolds-averaged Navier-Stokes/ Large-Eddy Simulation (RANS/LES) techniques to solve an aerodynamic flow field by applying the unsteady, compressible, hyperbolic Navier–Stokes equations of second order. The two-layer SSG/LRR- ω differential Reynolds stress turbulence model presented, combining the Launder- Reece-Rodi (LRR) model near walls with the Speziale-Sarkar-Gatski (SSG) model further apart by applying Menter's blending function F1. Herein, Menter's baseline ω-equation is exploited for supplying the length scale. Another emphasis is put on the anisotropic description of dissipation at close distance to the solid wall or in wake area for describing the friction-induced surface-roughness behaviour in viscous fluid physics and swirling wake effects. For that purpose, the SSG/LRR-ω seven-equations Reynolds stress turbulence model with anisotropic extension was realized, therefor the theory is described in general. Beyond that, a modified delayed detached-eddy simulation (MDDES) and a scale adaptive simulation (SAS) correction to capture the stochastic character of a large-eddy-type unsteady flow with massive flow separations in the broad band is implemented. To demonstrate the time-dependent noise propagation having wave interference a linearized Euler equation (LEE) model using a combined Momentum- and Lamb-vector source have been applied into the CFD/CAA - method. The DLR 15 wing, a High-Lift device in landing configuration having a deployed slat and landing flap is studied experimentally and numerically. The first part of the application deals with the steady flow investigation; however, the same turbulence model is used for the unsteady flow case without the enclosed time derivatives. The second part concentrates on unsteady modelling for the Navier–Stokes and Linearized Euler field. With this new combined CFD/CAA - method, steady and unsteady numerical studies for the high-lift wing configuration for discovering the aerodynamic and –acoustic propagation effects are shown, discussed and when experimental data were available validated. The High-Lift wing has a constant sweep angle of Λ=30° to investigate possible cross-flow; to realize this, periodic boundary conditions were set in spanwise direction","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124119229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical Dodecahed Microstrip Antenna Network Modeling for Femto Satellite","authors":"C. Hamrouni, R. Hamza","doi":"10.4172/2168-9792.1000196","DOIUrl":"https://doi.org/10.4172/2168-9792.1000196","url":null,"abstract":"The work focusses on antenna design based on fundamental Electromagnetic radiated element conception and a mathematical Dodecahed Microstrip Antenna Network Modeling for New Ultra Small Satellite (NUSS) development. Proposed solution meets ever increasing demands for improvements in inter station and Femto Satelite disconnection rates, and thus to synthesize the total radio transmission access USS visibility. We develop a new architecture for Dodecahed microstrip antenna elements which present a fundamental component of the overall system solution. The paper demonstrates mathematically: How proposed controlled antenna element combination operates, advanced selection and other related technologies can achieve substantial system performance for new USS generation.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132457558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nanosatellites - The Tool for a New Economy of Space: Opening Space Frontiers to a Wider Audience","authors":"G. García-Cuadrado","doi":"10.4172/2168-9792.1000192","DOIUrl":"https://doi.org/10.4172/2168-9792.1000192","url":null,"abstract":"Space is still a frontier. The advantages of research in microgravity conditions are still somehow a private niche \u0000 of big aerospace contractors and main space agencies. But the landscape is changing and an incipient effort is being \u0000 pursued to open space frontiers to small and medium-sized companies, universities, under-developed countries and \u0000 non-profits. We will revise the advantages of microgravity research and a tool to conduct it at low-cost, rapid response \u0000 and flexibility through the use of nanosatellites opening thus space frontiers to a wider audience. These highly \u0000 capable satellites can support a wide range of mission objectives, from pure research to technology demonstrators \u0000 and space qualification tests. The small satellites market is valued 600 M USD to 1.000 M USD yearly with an \u0000 estimated 2.200 to 2.700 needed launches in the 2015-2020 timeframe. We will also introduce a new launcher under \u0000 development to serve specifically the nanosatellite incipient market to help solve the scarce launching opportunities \u0000served today by conventional launchers.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129556366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined Method (1D + 3D) of the Axial TurbineâÂÂs Stage AerodynamicOptimization","authors":"A. Boiko, A. Usaty, D. Maksiuta","doi":"10.4172/2168-9792.1000191","DOIUrl":"https://doi.org/10.4172/2168-9792.1000191","url":null,"abstract":"The paper presents the optimization method of turbine stages based on step-by-step application of onedimensional and three-dimensional optimization techniques of the main stage geometrical parameters. Using the developed method, the optimization of the 3rd stage of high pressure steam turbine K-540-23.5 was carried out. As a result of optimization a new stage with an absolute efficiency increase more than 1% compared to the original design was obtained. The reasons leading to such performance boost were analyzed and are represented in the paper.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126090937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Buoyancy Explains Terminal Velocity in Skydiving","authors":"N. ell-Mills","doi":"10.4172/2168-9792.1000189","DOIUrl":"https://doi.org/10.4172/2168-9792.1000189","url":null,"abstract":"Estimates show that skydivers in free-fall displace a mass of air downwards equal to their own mass every second, in order to maintain a constant terminal velocity. This is also demonstrated at indoor skydiving centers where air blown upwards can suspend skydivers in mid-air. Like a boat floating in water, the skydiver is floating on air. Consequently, Archimedes principle of buoyancy can be used to explain the physics of terminal velocity in skydiving. Conventional physics explains that drag, the force needed to push air out of a skydiver’s path, sets a limit to a skydiver’s velocity. Which is correct but incomplete. It is more accurate to add that according to buoyancy, the skydiver’s velocity will increase until a mass of air equal to his own mass is displaced each second. Drag on a skydiver is defined by the equation: Drag = 0.5 (Velocity2 × Air Density × Surface Area × Drag Coefficient) This equation has severe limitations as It relies on a drag coefficient which must be already known in order to calculate terminal velocity. Worse, this drag coefficient cannot be directly measured and changes constantly. Why is this important? This demonstrates that buoyancy applies to objects that move and is measured over a one second time period. At present, buoyancy is only applied to stationary objects, such as boats or balloons. Also, buoyancy provides a simpler and more accurate method to estimate terminal velocity, without having to know the drag coefficient. This paper predicts that all objects falling at terminal velocity will displace a mass of fluid equal to their own mass each second to maintain buoyancy and a constant terminal velocity. An explanatory video: “Buoyancy explains terminal velocity in skydiving,” is available on youtube, on channel of ‘N Landell’ (the author of this paper).","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127905050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Conceptual Study Towards Delivery of Consumable Materials to AircraftAssembly Stations Performed by Mobile Robots Based on Industry 4.0Principles","authors":"Barbosa Gf, Hern, es Ac, S. Luz, J. Batista, Nunes Va, M. Becker","doi":"10.4172/2168-9792.1000187","DOIUrl":"https://doi.org/10.4172/2168-9792.1000187","url":null,"abstract":"This paper aims to present a conceptual study that integrates mobile robots and communication systems developed for delivery of materials to workstations of aircraft assembly lines. In the interest of providing deliveries of material in heights, a concept of a customized UAV (Unmanned Aerial Vehicle) has been proposed herein in order to assist the labor needs related to logistics requirements. A picker aerial vehicle has been designed to perform the operations through a man-machine interaction based on a proper software application developed for this specific intention. In order to integrate this whole process, an AGV (Automated Guided Vehicle) is used to deliver the materials on the floor and to transport the proper aerial vehicle to take-off in specific places. Accordingly, it is understood that these integrated automated systems commanded by CPS (Cyber-Physical Systems) could manage the information, perform tasks and contribute to a better process. Therefore, the major contribution and novelty of this paper is to show how an adapted UAV in conjunction with a special AVG and a tailor-made software application could bring several benefits to the aircraft manufacturing industry. Thus, this approach has looked for better results in terms of productivity, safety of people and costs related to down-time, number of ground support equipment and wastes associated with movements. A case study has demonstrated earnings of approximately USD 300 k per year. This proposal can also improve the flexibility of work tasks; manage production routines due to the balancing of the assembly line and easiness to attend requests online, adding value and providing a greater efficiency of the process based on Industry 4.0 trends. A proper framed-model is presented as a novelty in order to evidence advantages reached when robotics and internet of things are combined.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127017815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Avionics Compartment Fire Extinguishing on the Commercial Airplanes","authors":"Behbahani-Pour Mj, G. Radice","doi":"10.4172/2168-9792.1000188","DOIUrl":"https://doi.org/10.4172/2168-9792.1000188","url":null,"abstract":"In all commercial and non-commercial airplanes, there is no fire detection or fire extinguishing system in the avionics bay. Racks, are cooled by ambient or conditioned air. Each rack will include several circuit boards, which in case of overheat, can burn with the risk of igniting the surrounding components and structures, thus jeopardizing flight safety. It becomes therefore important to provide fire detection and fire extinguishing capabilities in the aircraft avionics compartment. The approach proposed in this paper, extracts nitrogen from ambient air by mean of the Air Separator Module, then nitrogen is routed to the avionics compartment racks, and enters inside the component and extinguishes the fire. The temperature of the nitrogen is adjusted to be around 25°C to prevent thermal shock effects on the circuit boards before being injected in the avionics compartment. A series of experiments conducted, aimed at gathering information by using dry nitrogen under different pressure values to extinguish different size of fire. The analysis of the experiment research showed that increasing nitrogen pressure, resulted in quicker extinguishing time. This is because nitrogen under higher pressure, quickly decrease the oxygen concentration in the air for the fire already in the process of combustion. Nitrogen does not conduct electricity thus cause no short circuits during and after the extinguishing process, therefore, they are ideal for use in the electronic systems.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124224573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of Sloshing in Rigid Rectangular Tank and a Typical Aircraft Drop Tank","authors":"Shreeharsha Hv, S. Sg, Mallikarjun Sg","doi":"10.4172/2168-9792.1000186","DOIUrl":"https://doi.org/10.4172/2168-9792.1000186","url":null,"abstract":"In this research, the liquid sloshing behavior in a 3D rectangular tank was simulated and validated by applying peak acceleration load using computational fluid dynamics technique. The application of this sloshing phenomenon was carried out on a typical Aircraft Drop tank with and without baffle plates for 7 g peak acceleration. The structural integrity of the drop tank has been taken into consideration during the cruise flight condition. Further, an optimized design of a drop tank has been modeled. The comparison of computed results for 3D rectangular tank case with experimental results showed that the numerical technique is capable of simulating hydrostatic pressure loads exerted on tank walls. Similarly, the necessary sloshing loads in the form of hydrodynamic pressure generated on the tank walls have been estimated for different cases of a typical aircraft drop tank. The kinematic profiles of liquids were observed at different instances for various cases. Computational results indicated that there is a reduction in the peak pressure on aft side of the tank with the use of baffle plates.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"16 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134571384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calculation of the Flight Characteristics of the Aircraft, AN-225","authors":"M. Sherif El Sayed Ahmed Soliman","doi":"10.4172/2168-9792.1000183","DOIUrl":"https://doi.org/10.4172/2168-9792.1000183","url":null,"abstract":"Flight dynamics - The science of the laws of motion of aircraft under the influence of wind, gravity, and reaction forces. It is a combination of mainly three classic disciplines: solid mechanics, fluid dynamics, and mathematics. Among the wide range of problems in the dynamics of flight of great practical importance are the problems connected with the study of the steady rectilinear motion of the aircraft. The solution allows them to determine the flight characteristics of the aircraft, characterized by the range of possible speeds and heights, rate of climb, range, flight time, and so on.","PeriodicalId":356774,"journal":{"name":"Journal of Aeronautics and Aerospace Engineering","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116031406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}