فهرست مطالب

مهندسی شناورهای تندرو - پیاپی 41 (بهار و تابستان 1391)

نشریه مهندسی شناورهای تندرو
پیاپی 41 (بهار و تابستان 1391)

  • تاریخ انتشار: 1391/04/30
  • تعداد عناوین: 10
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  • R. Ebrahimilale, Dr .M. Salari Page 4
    Stealth technology is increasing abilitysurvive formilitaryshipscontraryidentificationand targetingsensors,thereforemodulerequires for value detectionand identificationof the ships by detectors.One of the suitable methodsformeasuring signature ship is simulate by computer. Thermal radiation one of the signatures of the vessel’s hull is by passive thermal detector in the all time of day and night. Inthispaper expressed the effective parametersforcomputer simulationsof thermalinfraredradiationof the hull’s ship toestimateradiationandcondition of the thermalinfrareddetectors identification.
    Keywords: Thermal Radiation, Infrared (IR), Simulation, Vessel's hull, Stealth technology
  • H. Malakizade, M. Moradi Page 20
    In this article, the designing of comparative-sliding mode controller for ship’s dynamic fin-roll stability in the presence of disturbances is presented. For designing the controller, at first non-liner model of desired system is studied, then the uncertainty is entered into the system model and by using the designing of sliding mode methods, the desired controller is designed. As the disturbance range information is not always available, selecting an appropriate rate coefficient foe sliding mode controller is very difficult. To solve this problem, in this article, the comparative method for setting the controller is presented. To prove the stability, the Liapanov method is used. To study the function of the loop system, the performed simulation and its obtained results from the comparative-sliding mode controller by PID control method are compared. The results show that the suggested methods have better function than PID ones.
    Keywords: Ship's dynamic fin, roll, comparative control, sliding mode, resistance fin, roll control
  • M. Mohammadbeygi, M. Sajedi Page 32
    Extremist vessels due to the rapid movement of fluid and changes in body edge Planning and hydrophilic And cavitation bubble due to the pressure of the changing pace of change emerges parts and butterflies drift in the phenomenon of cavitation bubble is created.This phenomenon can be used to increase desired speed is Extremist and adverse effects such as corrosion and shock forces that can bring a tear to the body.In this paper how the emergence of this phenomenon and the mechanisms briefly discussed.
    Keywords: Bubbles, cavitation, cavitation bubble, cloud cavitation, cavitation layer, military applications, reducing the adverse effects of cavitation
  • A. Eghdami, A. Hajizade Page 46
    Piston and connecting rod are the most sensitive moving mechanical parts in engine which must have very special features. In this article, because of importance of the breaking down of piston and connecting rod in high-round marine engines, we are trying by using the performed investigation and our different experiences and also those of mechanics of sea areas, so give an analytical reasons for the failure of these two parts and give an technical suggestion for improving and increasing the long life these two parts and consequently the long life of the engine.
    Keywords: Engine, ceasing, piston, connecting rod, oil, power, torque, relative speed
  • M. Sajedi, E. Faghihi Page 56
    There are different methods to determine the Hydrodynamical coefficient of naval structures. In this article. A two-dimensional hydrofoil with angles 2, 4, 5 & 7 is analyzed hydrodynamically through “Ansys 13” software. Their drag coefficient with an empirical model, tested by emillio and angello group in 2003 in water tunnel [1]. Also in recent years many other scientists has worked on this model. This article has a closer answer compared to the experienced one. (y is between 20to 150 and Rinold’s number of the tested model is 8E5).
    Keywords: Hydrofoil, hydrodynamics, ansys 13, drag coefficient, water tunnel
  • K. Shojaei, E. Faghihi Page 68
    In aim of writing this article is to study the efficiency of changing ground engines to the naval one considering the environmental operation condition of ground engine and their ratio of smallness to the power of these engines. So, changing the main structure of ground engine for this purpose is not possible and needs a new design and structure. By changing the parameter of mid-effective pressure of engine power can achieve this purpose and increase the engine power. Considering the environmental operation condition of these engines, sea water can be used for cooling purposes.
    Keywords: Naval engines, mid, effective pressure, volume efficiency, brake power, mechanical efficiency
  • F. Mosavipur, Na Zareie Page 80
    In this article,two methods of repetitiveCalmenfilter and continuous repetitiveCalmen for omitting the noise resulting from the sound ofhighspeed vessel engines in communication contacts are studied.These two methods are the most important methods of filtering which is used in speech improvement. These algorithms from the mass computation point of view,function efficiency, and the used memory was taken into consideration. SNR item criterion and PESQ for improved speech quality evaluation, was taken into work. These two algorithms are simulated on three types of noises (white, pink, and industrial ones). The results of implementation of these algorithms show that the function of continuous repetitiveCalmen in comparison to that of repetitiveone in omitting the noise is weaker, and as a result, the quality of acquired sound from repetitiveCalmen algorithm is more than other algorithms. To improve the efficiency, some solutions are offered through which by decreasing the amount of computations, the processing is very much desirable.
    Keywords: noise omission, Calmenfilter, speech quality, computation cost, high speed vessel
  • M. Sadeghijale, J. Barsani Page 94
    Electric propulsion system is the most important part of many ships and submarines. Because of the importance of the subject, this system is necessary to have some advantages such as little volume and weight, little noise, high efficiency, and so on. The decrease of produced noise level in submarines,specially by propulsion system, can help the stealth of submarine. In addition to the above-mentioned advantages, the propulsion system must have a high reliability and rarely be necessary to be maintained. Considering the mentioned advantages and the special properties of permanent magnet synchronous motor, it will be more convenient to use these kinds of motors for submarine propulsion system. In this article, by explaining the control strategies for this motor, we express the strength and weaknesses of these strategies. And finally, by comparing the stated control strategies for PMSM motor, we analyze the attitude about this motor which may be encountered by manufacturers of electric propulsions and discuss the way to increase the reliability of this system and implementing it.
    Keywords: electric propulsion system, permanent magnet synchronous motor, field oriented control, direct control of torque, flux
  • Ar Ghasemi, M. Salari, A. Behroozvaziri Page 106
    In this research, we study the effect of the composite high speed planning vessel hull stroke on water surface. To improve the hull ofhigh speed planning vessel against the impact of water, an appropriate reason was offered and this reason was tested for a real available vessel and the consequent results were presented. Finally, the thickness of the hull of the tested vessel was decreased in the composite sandwich panel core and by reinforcing the hull structure, the weight of the vessel was decreased in 17.6% percent. The acquired results from the direct limited element on improved vessel hull, will meet the limitations of DNV standards. At the end, the result of optimization was similar confidence coefficient (according to DNV standards) and steady strain distribution for different parts of the vessel hull.
    Keywords: high speed planning vessel, slamming, Dead, rise angle, Composite sandwich panel core, Hydrodynamic pressure, Dynamic explicit analysis