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Developing the Framework for Integrating Autonomous Unmanned Aircraft Systems into Cloud Seeding Activities 开发将自主无人机系统集成到人工降雨活动中的框架
Pub Date : 2016-09-03 DOI: 10.4172/2168-9792.1000172
T. DeFelice, D. Axisa
This paper introduces an engineering approach to develop autonomous unmanned aircraft systems technology for integration in future weather modification (cloud seeding) programs with the goal to improve operational efficiency and evaluation accuracy. It builds upon the process already established in a previous paper by Axisa and DeFelice who constructed a framework underlying the development of new technologies for use in cloud seeding activities, identifying their potential benefits and limitations and providing initial guidance
本文介绍了一种开发无人驾驶飞机系统技术的工程方法,用于未来人工影响天气(云播)计划的集成,目的是提高操作效率和评估准确性。它建立在Axisa和DeFelice之前的一篇论文中已经建立的过程之上,他们构建了一个用于云播活动的新技术开发的框架,确定了它们的潜在好处和局限性,并提供了初步指导
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引用次数: 4
Secchi disk depth: Evaluation of an algorithm based on new visibility theory 塞奇盘深度:一种基于新可见性理论的算法评价
Pub Date : 2016-08-02 DOI: 10.4172/2168-9792.C1.014
Zhongping Lee, S. Shang
S disk depth (ZSD), a measurement of the maximum viewable depth of a white or black-and-white disk with a diameter about 30 cm when lowered into water, holds the longest (from at least 1880’s) records of water transparency. This ZSD data record is found not only important for the study of climate change, but also useful for seagoers. However, there has been no standard ZSD product from all satellite ocean color missions. This may in part lie in that there was no robust algorithm to estimate ZSD of global oceans from ocean color measurements, although numerous empirical relationships were developed for various locations. In addition, the classical visibility theory suggests that ZSD is proportional to the inverse of (K+c), with K the diffuse attenuation coefficient and c the beam attenuation coefficient. Because c is significantly (2-5 or more) larger than K and that c could not be analytically retrieved from ocean color remote sensing, it has been perceived that there could be no analytical or semi-analytical algorithm for ZSD from ocean color measurements. A recent study found that this classical interpretation of ZSD is flawed, and a new theoretical relationship is developed for ZSD. With concurrent measurements of ZSD and remote-sensing reflectance (Rrs) of wide range of aquatic environments, the performance of the estimation of ZSD with Rrs as inputs by the classical and the new approaches is evaluated. The excellent results of the new relationship indicate a robust system to produce global ZSD from satellite ocean color measurements.
S圆盘深度(ZSD)是一个测量白色或黑白圆盘的最大可见深度,直径约为30厘米,当放入水中时,它保持着最长的水透明度记录(至少从1880年开始)。发现这一ZSD数据记录不仅对研究气候变化很重要,而且对航海者也很有用。然而,所有卫星海洋颜色任务都没有标准的ZSD产品。部分原因可能在于,尽管在不同地点建立了许多经验关系,但没有可靠的算法来从海洋颜色测量中估计全球海洋的ZSD。此外,经典能见度理论认为ZSD与(K+c)的倒数成正比,其中K为漫射衰减系数,c为光束衰减系数。由于c明显(2-5或更大)大于K,并且c无法从海洋颜色遥感中分析获取,因此人们认为,从海洋颜色测量中无法获得ZSD的分析或半分析算法。最近的一项研究发现,这种对ZSD的经典解释是有缺陷的,并为ZSD建立了一种新的理论关系。通过同时测量大范围水生环境的ZSD和遥感反射率(Rrs),评估了传统方法和新方法以Rrs为输入估计ZSD的性能。新关系的良好结果表明,从卫星海洋颜色测量中产生全球ZSD的系统是可靠的。
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引用次数: 6
Determination of the Earths Magnetic Field Gradients from SatellitesMeasurements and Their Inversion over the Kursk Magnetic Anomaly 卫星测量地球磁场梯度的测定及其在库尔斯克磁异常上的反演
Pub Date : 2016-06-30 DOI: 10.4172/2168-9792.1000164
K. Kis, P. Taylor, G. Wittmann
We computed magnetic field gradients at satellite altitude, over Europe with emphasis on the Kursk Magnetic Anomaly (KMA). They were calculated using the CHAMP satellite total magnetic anomalies. Our computations were done to determine how the magnetic field observations data from the new ESA/Swarm satellites could be utilized to determine the structure of the magnetization of the Earth’s crust, especially in the region of the KMA. Ten years of CHAMP data were used to simulate the Swarm data. An initial east magnetic anomaly gradient map of Europe was computed and subsequently the North, East and Vertical magnetic gradients for the KMA region were calculated. The vertical gradient of the KMA was also determined using Hilbert transforms. Inversion of the total KMA was derived using Simplex and Simulated Annealing algorithms. The depths of the upper and lower boundaries are calculated downward from the 324 km elevation of the satellite. Our resulting inversion depth model is a horizontal quadrangle. The maximum errors are determined by the model parameter errors.
我们计算了欧洲上空卫星高度的磁场梯度,重点是库尔斯克磁异常(KMA)。它们是用CHAMP卫星的总磁异常计算出来的。我们的计算是为了确定如何利用新的ESA/Swarm卫星的磁场观测数据来确定地壳的磁化结构,特别是在KMA区域。10年的CHAMP数据被用来模拟Swarm数据。首先计算了欧洲东部的初始磁异常梯度图,然后计算了KMA地区的北、东和垂直磁异常梯度。利用希尔伯特变换确定了KMA的垂直梯度。利用单纯形和模拟退火算法推导了总KMA的反演。上下边界的深度是从卫星324公里高度向下计算的。我们得到的反演深度模型是一个水平四边形。最大误差由模型参数误差决定。
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引用次数: 0
Aerodynamic Analysis of Multi Element Airfoil 多单元翼型气动分析
Pub Date : 2016-06-30 DOI: 10.4172/2168-9792.1000171
D. Udayakumar, S. Kannan, Vimal Ch, R. Sriram, C. Ganapathi
The flow over multi-element airfoils has been numerically investigated in ANSYS fluent and has been compare the aerodynamic parameters with the standard NACA airfoils 4412 and 0012. The 2D viscous, transient, pressure model equations together with the k-ω turbulence model were applied to this numerical simulation utilizing the multiblock unstructured grids of sphere of influence type. Numerical results showed that the aerodynamic parameters of multi element airfoils with tail effect are much optimum than the standard NACA airfoils. Also the analysis is made on different flap and slat angles of different conditions and the optimization of multi element airfoils has been performed.
在ANSYS fluent中对多单元翼型的流动进行了数值研究,并与标准NACA 4412和0012翼型的气动参数进行了比较。采用影响球型多块非结构网格,将二维粘性、瞬态、压力模型方程和k-ω湍流模型应用于数值模拟。数值计算结果表明,考虑尾效应的多单元翼型气动参数比标准NACA翼型优化得多。对不同工况下不同襟翼和翼板角度进行了分析,并对多单元翼型进行了优化设计。
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引用次数: 9
CFD Analysis on Can-Type Combustor and Variation of Air Injection Angle under Typical Engine Condition 典型发动机工况下can型燃烧室及喷气角变化CFD分析
Pub Date : 2016-06-30 DOI: 10.4172/2168-9792.1000170
Pradhani Nl, A. Rajesh, Ganesha Prasad Ms
A computational prediction of combustion is a challenging task due complexity involved in the flow parameters. The design of can-type combustor has been considered for a special purpose using producer gas as fuel to run the turbine blades of a turbocharger. Producer gas used for power generation has zero effect, even though it emits CO2 into the atmosphere. The application has its background in finding an optimal turbocharger for matching the requirements of an IC engine. Non-premixed combustor is taken into account because producer gas having high temperature around 300 K when entering into combustion chamber, thus it is unsafe to operate in the premixed mode to prevent explosion in the air-fuel inlet and also simplifies the design. By changing the inlet air injection angle will affect the combustion parameters like low pressure drop, NOx level, outlet temperature, and wall temperature not to exceed 700 K. A mild steel material has been selected for computational prediction of flow behaviors under typical engine condition in can-type combustor. Thus for the initial consideration, basic design of a can-type combustor without a liner has been modeled. The specifications were met and checked for different combination of primary and secondary air injection duct and a most feasible configuration is obtained. The main aim is to optimize the characteristics of a combustor for a turbocharger test rig, i.e. the combustor designed has to be meet optimum condition, which is prevailing in the producer gas engine (formerly diesel engine).
由于流动参数的复杂性,燃烧的计算预测是一项具有挑战性的任务。考虑了一种特殊用途的罐式燃烧室的设计,该燃烧室使用产气作为燃料来驱动涡轮增压器的涡轮叶片。用于发电的生产者气体即使向大气中排放二氧化碳,也没有任何影响。该应用程序的背景是寻找符合IC发动机要求的最佳涡轮增压器。考虑了非预混燃烧室,因为产气进入燃烧室时温度在300 K左右,因此在预混模式下运行是不安全的,可以防止进气口爆炸,也简化了设计。通过改变进气喷射角度,会影响低压降、NOx水平、出口温度、壁面温度等燃烧参数,不超过700k。选取了一种低碳钢材料,对典型发动机工况下罐式燃烧室的流动特性进行了计算预测。因此,为了初步考虑,对无衬板的罐式燃烧室的基本设计进行了建模。对不同的一次和二次风管组合进行了规格检验,得到了最可行的配置形式。主要目的是优化涡轮增压器试验台燃烧室的特性,即燃烧室的设计必须满足最优条件,这在燃气发动机(原柴油发动机)中是普遍存在的。
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引用次数: 3
Design and Realization of Payload Operation and Application System ofChinas Space Station 中国空间站载荷运行与应用系统的设计与实现
Pub Date : 2016-06-12 DOI: 10.4172/2168-9792.1000169
H. Wang, L. Guo, P. Wu
China's Space Station will be launched in the year 2018; this space station is China's largest space science experiment and application platform until now. This paper mainly introduces the function composition of payload operation and application system of China’s space station, system architecture, hardware architecture and the new technology we use to implement the payload operation and application ground system of China's space station.
中国的空间站将于2018年发射;该空间站是迄今为止中国最大的空间科学实验和应用平台。本文主要介绍了中国空间站有效载荷运行与应用系统的功能组成、系统结构、硬件结构以及实现中国空间站有效载荷运行与应用地面系统所采用的新技术。
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引用次数: 0
Current issues in Space Situational Awareness (SSA) and Space Traffic Management (STM) 空间态势感知与空间交通管理的研究现状
Pub Date : 2016-05-05 DOI: 10.4172/2168-9792.C1.013
Marc Skinner
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引用次数: 211
NACA653218 Airfoil Aerodynamic Properties NACA653218翼型气动性能
Pub Date : 2016-05-03 DOI: 10.4172/2168-9792.1000168
Eslam E. AbdelGhany, O. Abdellatif, G. Elhariry, E. Khalil
In this research we have obtained the drag and lift coefficients, velocity, pressure and path lines contours using CFD which can also be determined by using wind tunnel experimental test. This process is relatively difficult and surely price more than CFD technique cost for the same problem solution. Thus we have gone through analytical method then it can be validated by experimental testing. A CFD procedure is described for determination aerodynamic characteristics of subsonic NACA653218 airfoil. Firstly, the airfoil model shape, boundary conditions and meshes were all formed in GAMBIT® 2.3.16 as a pre-processor. The second step in a CFD model should be to examine the effect of the mesh size on the solution results. In order to save time take case for a grid with around 100000 cells. The third step is validation of the CFD NACA653218 airfoil shape model by different turbulence models with available experimental data for the same model and operation conditions. The temperature of free stream is 288.2 K, which is the same as the environmental temperature. At the given temperature, the density of the air is ρ=1.225kg/m3, the pressure is 101325 Pa and the viscosity is μ=1.7894×10-5 kg/m s. A segregate, implicit solver is utilized (FLUENT® processor) estimate were prepared for angles of attack variety from -5 to 16°. The Spalart-Allmaras turbulence model is more accurate than standard k – e model, RNG k – e model and standard model k–e models. For lift coefficient, it is found maximum error by Spalart-Allmaras model about 12% lower than other turbulence models. For drag coefficient, it is found maximum error by Spalart-Allmaras model about 25% lower than other turbulence models. For pitching moment coefficient, it is found maximum error by Spalart-Allmaras model about 30% lower than other turbulence models.
本研究利用CFD计算得到了阻力和升力系数、速度、压力和路径线轮廓,并通过风洞实验测试确定。这一过程相对困难,对于同样的问题解决方案,肯定比CFD技术的成本要高。因此,我们已经通过了分析方法,然后可以通过实验测试来验证。介绍了亚音速NACA653218翼型气动特性的CFD计算方法。首先,在GAMBIT®2.3.16中作为预处理程序形成翼型模型形状、边界条件和网格。CFD模型的第二步应该是检查网格尺寸对求解结果的影响。为了节省时间,以大约100000个单元格的网格为例。第三步,在相同的模型和运行条件下,采用不同的湍流模型对CFD NACA653218翼型模型进行验证。自由流温度为288.2 K,与环境温度相同。在给定温度下,空气的密度为ρ=1.225kg/m3,压力为101325 Pa,粘度为μ=1.7894×10-5 kg/m s。利用FLUENT®处理器对-5 ~ 16°的迎角变化进行了分离、隐式求解。Spalart-Allmaras湍流模型比标准k - e模型、RNG k - e模型和标准模型k - e模型精度更高。对于升力系数,Spalart-Allmaras模型的最大误差比其他湍流模型小12%左右。对于阻力系数,Spalart-Allmaras模型的最大误差比其他湍流模型小25%左右。对于俯仰力矩系数,Spalart-Allmaras模型的最大误差比其他湍流模型小30%左右。
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引用次数: 0
Analyze the Mode Transition Logic of Automatic Flight Control System using Semi-Formal Approach 用半形式化方法分析自动飞行控制系统的模式转换逻辑
Pub Date : 2016-04-28 DOI: 10.4172/2168-9792.1000167
Rathina Kumar, J. Jayanthi
Autopilot system is a highly critical avionics system in modern aircraft as it steers the aircraft automatically. The autopilot is a highly complex system driven by a complex logic and is one of the major reasons for the accidents in automated airliner. The autopilot logic consists of the mode-transition logic which in automated mode steers the aircraft based on the aircraft aerodynamics. In the automated mode the correct and efficient working of the modetransition is highly critical; hence a high assurance approach is required to analyze the logic for its functionality and performance. In this paper, we present a semi-formal method based approach to analyze and validate the Mode-Transition Logic (MTL) for an indigenously developed commercial aircraft in the vertical and lateral directions. The MTL is analyzed and validated for its correct, complete, and reliable functionality and operation using Stateflow. The modeled MTL logic is validated for the allowed transitions based on the input combinations against the requirements for functionality and safety. The outcome of the approach shows encouraging results with respect to assurance in functionality, performance and safety in comparison to the conventional manual approach of testing. Similar semiformal based approach can be used to reduce the design effort in the design and development of complex system designs as compared to the manual analysis.
自动驾驶仪是现代飞机中非常关键的航电系统,它能自动操纵飞机。自动驾驶仪是一个由复杂逻辑驱动的高度复杂的系统,是造成自动驾驶客机事故的主要原因之一。自动驾驶逻辑由模式转换逻辑组成,模式转换逻辑在自动模式下根据飞机空气动力学原理对飞机进行操纵。在自动化模式下,正确、高效地进行模式转换至关重要;因此,需要一种高保证方法来分析其功能和性能的逻辑。在本文中,我们提出了一种基于半形式化方法的方法来分析和验证自主开发的商用飞机在垂直和横向方向上的模式转换逻辑(MTL)。使用statflow分析和验证MTL的正确、完整和可靠的功能和操作。建模的MTL逻辑根据功能和安全需求的输入组合验证允许的转换。与传统的手动测试方法相比,该方法的结果在功能、性能和安全性方面显示出令人鼓舞的结果。与手工分析相比,可以使用类似的基于半形式化的方法来减少复杂系统设计和开发中的设计工作量。
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引用次数: 0
Design and Structural Analysis of Solid Rocket Motor Casing Hardwareused in Aerospace Applications 航天用固体火箭发动机机壳硬件设计与结构分析
Pub Date : 2016-04-28 DOI: 10.4172/2168-9792.1000166
B. Dineshkumar, B. ShishiraNayana, D. ShravyaShree
Rocket motors are widely used to generate thrust or impulsive force to impart a desired velocity to flight vehicle to transport its payload to the intended destination. The working principle of Rocket motor is mainly Newton’s 2nd and 3rd laws. Rocket motors are non-air breathing propulsion class i.e., won’t require oxygen from the atmosphere for combustion of the fuel which is stored in the rocket motor. During the operating conditions of the motor hardware, it will be subjected to high temperatures and pressure loads. Structural and thermal design has to carried out for a given input parameters and analysis to be carried out to check the stress levels and temperatures on the hardware. The present paper deals with structural design of motor hardware. The main input parameters considered are the maximum operating pressure and maximum diameter of the Motor hardware. The material properties considered are up to 100°C. Structural analysis and fracture analysis are to carry out after the design of each component of the rocket motor hardware. For design, the motor hardware is considered as a pressure vessel. To compute parameters like thickness some initial assumptions were made. 2D drawing is developed using Auto Cad software and structural analysis is carried out in ANSYS. This software employs finite element analysis techniques to generate the solution. Hence the displacement magnitude, von mises stress and strain developed within the motor is pictorially visualized. Fracture analysis is also carried out on the material.
火箭发动机被广泛用于产生推力或冲力,以赋予飞行器所需的速度,以将其有效载荷运送到预定的目的地。火箭发动机的工作原理主要是牛顿第二和第三定律。火箭发动机是非空气呼吸推进级,即不需要大气中的氧气来燃烧储存在火箭发动机中的燃料。在电机硬件运行的条件下,它将受到高温和压力负载。必须针对给定的输入参数进行结构和热设计,并进行分析以检查硬件上的应力水平和温度。本文论述了电机硬件的结构设计。考虑的主要输入参数是电机硬件的最大操作压力和最大直径。考虑的材料性能最高可达100°C。在对火箭发动机硬件各部件进行设计后,进行结构分析和断裂分析。在设计时,电机硬件被认为是一个压力容器。为了计算厚度等参数,进行了一些初始假设。利用Auto Cad软件绘制二维图纸,在ANSYS中进行结构分析。该软件采用有限元分析技术生成解。因此,位移幅度,冯米塞斯应力和应变发展在电机图形可视化。对材料进行了断裂分析。
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引用次数: 4
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Journal of Aeronautics and Aerospace Engineering
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