Research Paper
farshad shamlu; Abolghasem Naghash
Volume 10, Issue 2 , September 2017, Pages 1-8
Abstract
In this study, a different approach to the prediction of satellite position is introduced.All methods are based on the Kepler’s laws of planetary motion and the orbitalperturbations such as the Earth’s oblateness, atmospheric drag, third-body perturbationand the solar-radiation pressure. ...
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In this study, a different approach to the prediction of satellite position is introduced.All methods are based on the Kepler’s laws of planetary motion and the orbitalperturbations such as the Earth’s oblateness, atmospheric drag, third-body perturbationand the solar-radiation pressure. All these perturbations are modeled and are includedseparately in the equation. However, this paper offers a new view of the prediction whichsuggests the use of artificial neural networks and observation data. The advantage of thismethod is based on the usage of observation data, so that all disturbances are taken intoaccount and there is no need to use perturbation models. For this reason, the use of theTLE as the most reachable actual data is considered. Comparison of the output of thismethod with actual data shows the accuracy of the proposed method which is very high.
Research Paper
sahand majidi; Mostafa Esmaili
Volume 10, Issue 2 , September 2017, Pages 9-21
Abstract
Liquid sloshing of a partially filled container subject to surge and pitch motions isnumerically investigated using a sophisticated numerical algorithm. The algorithm isdeveloped based on the finite volume methodology and volume of fluid (VOF) technique isutilized to capture the interface evolution and ...
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Liquid sloshing of a partially filled container subject to surge and pitch motions isnumerically investigated using a sophisticated numerical algorithm. The algorithm isdeveloped based on the finite volume methodology and volume of fluid (VOF) technique isutilized to capture the interface evolution and deformation. Also, the interface capturingquality of the developed flow solver is enhanced due to its coupling to THINC interfacesharpening technique. The numerical results are validated through the comparison of theinterface deformation amplitude and the frequency with the available experimental andanalytical data for liquid sloshing caused by lateral sinusoidal accelerations withresonance and non-resonance frequencies. Moreover, liquid sloshing due to angularexcitations are studied for two different tank geometries with and without dampingbaffles. The resulting pressure oscillations of the pressure exerted on the side walls aremonitored and compared to the experimental data.
Research Paper
Hossein Mahdavy-Moghaddam; mohammad hadi Hamedi
Volume 10, Issue 2 , September 2017, Pages 23-32
Abstract
Recently, a novel technique using dual throat nozzles is introduced for thrustvectoring applications. The present paper discusses this new technique. All thrustvectoring techniques are evaluated with some common parameters: nozzle dischargecoefficient, system thrust ratio, thrust vector angle and thrust ...
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Recently, a novel technique using dual throat nozzles is introduced for thrustvectoring applications. The present paper discusses this new technique. All thrustvectoring techniques are evaluated with some common parameters: nozzle dischargecoefficient, system thrust ratio, thrust vector angle and thrust vectoring efficiency. For agiven micro turbine nozzle geometry, a double throat nozzle is designed usingdimensional scaling or geometrical analogy. Then, by comparing the results obtainedfrom a designed geometry for discharge coefficient, thrust vector angle and thrust vectorefficiency, the DTN performance is reported. The designed DTN deflected the vectorangle of 18 degrees with the fluidic injection flow rate equal to 10 percent of the primaryflow rate.
Review Paper
Masoud Ebrahimi Kachoie; Mohammadvali Arbabmir; Mohammad Norouz
Volume 10, Issue 2 , September 2017, Pages 33-52
Abstract
Inertial navigation system error increases due to sensor errors with the increase intime. Usually, to prevent the growth of navigation system error, inertial navigationsystems are integrated with sensors or auxiliary systems. The importantly aided system isGNSS. Because of GNSS outage or its invalidity, ...
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Inertial navigation system error increases due to sensor errors with the increase intime. Usually, to prevent the growth of navigation system error, inertial navigationsystems are integrated with sensors or auxiliary systems. The importantly aided system isGNSS. Because of GNSS outage or its invalidity, the other auxiliary sensors are used toincrease the accuracy of the inertial navigation system. In this article, the types ofmethods which are used by imaging camera for navigation or for the accuracyimprovement of an inertial navigation system for UAVs are discussed. After reviewing theliterature in the field of vision navigation in UAVs, the proper classification for visionnavigation methods and the development of these methods are presented. In UAVs, thevision navigation techniques are based more on Map metric, optical flow, featuretracking, odometers and simultaneous localization and mapping.
Hojat Taei; Mansour Hozuri; Amirhossain Adami
Volume 10, Issue 2 , September 2017, Pages 53-63
Abstract
The hydrazine propulsion system is one of the most widely used monopropellantpropulsion systems. This low-cost and low mass system is used for the attitude control ofsatellites due to its high specificity and rapid response.For this purpose, in the presentstudy, an optimal design of a hydrazine monopropellant ...
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The hydrazine propulsion system is one of the most widely used monopropellantpropulsion systems. This low-cost and low mass system is used for the attitude control ofsatellites due to its high specificity and rapid response.For this purpose, in the presentstudy, an optimal design of a hydrazine monopropellant propulsion system with the aim ofminimization of total mass and maximization of total impulse in the framework ofmultidisciplinary design optimization and sequential design method is considered. Inaddition, the principles of multidisciplinary and sequential design are described in thispaper. It has been tried to examine the impact of different elements on design goals andcompare the optimal value obtained in each of the design structures from differentaspects. It should be noted that the design process is accomplished in two ways, i.e.single-objective and multi-objective, and the optimal multidisciplinary design method iscompared with the sequential design method for the hydrazine monopropellant propulsionsystem.
Research Paper
Mohammad Moumivand; hasan mohammadkhani; javad heydari; mohammad hosein vaezi
Volume 10, Issue 2 , September 2017, Pages 65-72
Abstract
Determining aerodynamic coefficients and control and stability derivatives play animportant role in the development of flight vehicles. In this paper, roll damping coefficientof BASIC FINNER standard model is determined at different attack angles and withvarious Mach numbers using numerical Sliding Mesh ...
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Determining aerodynamic coefficients and control and stability derivatives play animportant role in the development of flight vehicles. In this paper, roll damping coefficientof BASIC FINNER standard model is determined at different attack angles and withvarious Mach numbers using numerical Sliding Mesh method. Also, the impact of theeffective parameters such as amplitude and frequency of oscillation, time step and numberof iteration in each step in numerical solution are investigated to determine the rolldamping coefficients. Geometry modeling and grid generation and the flow analysis aredone by ANSYS CFX and ANSYS FLUENT software, respectively. In this simulation,Euler’s flow equations, compressible and unsteady flow, finite volume method and densitybased solver with explicit formulation and first-order accuracy for a numerical solutionare used. To evaluate the results of a numerical study, a comparison is made between theexperimental data and MD results, indicating that the results have a good accuracy.
