• 동력기계공학회지
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• 제15권5호
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• pp.16-21
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• 2011

The large scale decisive battle will be gradually reduced on the sea in the future and surface combatant ship installed advanced weapon units as well as propulsion system will be continuously increased. The high level of military technology leads to appear state-of-the-art weapon system using high power energy. As a results, fossil fuel powered main prime mover as diesel engine and gas turbine which are composed of mechanical propulsion system should be decreased from combatant ship in the near future. The new building naval combatant ship with the latest technology has electric based propulsion method of the hybrid type combined with mechanical and electrical drive. U.S. and Royal Navy, especially, select the integrated fully electric based propulsion system for the next generation combat ship and play an important roll for developing them. In this context, this paper was focused on the deduction of implications through analyzing the combatant ship propulsion system using diesel and gas turbine engine which are promoted on the worldwide.

• 시스템엔지니어링학술지
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• 제16권2호
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• pp.110-117
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• 2020

In this paper, we estimated the straight line stability by performing a 3 degree of freedom spiral test simulation of a intact/damaged surface combatant using the hydrodynamic coefficient obtained through the PMM(Planar motion mechanism) test based on system engineering process. A model ship was ONR Tumblehome and damaged compartment was set on the starboard bow. As a result of conducting a spiral test simulation based on the experimental results of J.Ha (2018), the asymmetric straight line stability due to the damaged compartment was confirmed. In the case of a ship in which the starboard bow was damaged, it was confirmed that it had the characteristic to deflect to the left when going straight. Also, when estimating the straight line stability of a both port and starboard asymmetric surface combatant, a separated equation of motion model that sees the port and starboard as different ships seems suitable.

• 한국군사과학기술학회지
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• 제19권4호
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• pp.500-507
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• 2016

In order to increase the survivability of combatant ship, measuring and analyzing the infrared radiation is important. Consequently, providing analysis report is also important for the progress of the new combatant ship design. This paper proposes a design and software implementation of filtering for the noise reduction of mid-wave IR camera image. We reduced the total test cost by using the suggested software filtering technique instead of hardware replacement or re-calibration. In addition, we enhanced the accuracy of analysis results by adjusting the parameters of software filtering according to the results of filtered image.

• Strategy21
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• 통권34호
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• pp.178-206
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• 2014

The battlefield environment in the maritime has been changed by advanced IT technology, variation of naval warfare condition, and developed military science and technology. In addition, state-of-the-art surface combatants has become to multi-purpose battleship that is heavily armed in order to meet actively in composed future sea battlefield condition and perform multi-purpose missions as well as having capability of strategic strike. To maximize the combat strength and survivability of ship, it is not only possible for Zumwalt(DDG-1000) class combatant to conduct multi-purpose mission with advanced weapon system installation, innovative hull form and upper structure such as deckhouse, shipboard high-powered sensor, total ship computing environment, and integrated power control but it was designed so that can be installed with energy based weapon systems in immediate future. Zumwalt class combatant has been set a high value with enormous threatening surface battleship in the present, it seems to be expected that this ship will be restraint means during operation in the littoral. The advent of Zumwalt class battleship in the US Navy can be constructed as a powerful intention of naval strength building for preparing future warfare. It is required surface ship that can be perform multi-purpose mission when the trend of constructed surface combatants was analyzed. In addition, shipboard system has been continuously modernized to keep the optimized ship and maximize the survivability with high-powered detection and surveillance sensor as well as modularity of combat system to efficient operation.

• Ocean Systems Engineering
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• 제1권2호
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• pp.111-119
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• 2011

Mines, torpedoes and improvised explosive devices (IED) pose a serious threat to the survivability of naval combatants. Inasmuch, a major goal in the design of modern combatant ships has been to eliminate or at least reduce the devastating damage caused by underwater explosion events. Even though there has been extensive research performed on the various underwater explosion phenomena and their associated effects, effective shock testing and shock proofing strategies for naval ship systems have proven to be illusive. Through the use of modeling and simulation (M&S), live fire test and evaluation (LFT&E) and laboratory testing, general guidelines for the shock hardening of shipboard equipment and systems have been developed. In this paper, current aspect of ship survivability has been addressed and future direction is discussed.

• Ocean Systems Engineering
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• 제10권1호
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• pp.1-23
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• 2020

Hydrodynamic Drag of Surface combatants pose significant challenges with regard to fuel efficiency and exhaust emissions. Stern flaps have been used widely as an energy saving device, particularly by the US Navy (Hemanth et al. 2018a, Hemanth Kumar and Vijayakumar 2018b). In the present investigation the effect of flap turning angle on drag reduction is numerically and experimentally studied for a high-speed displacement surface combatant fitted with a stern flap in the Froude number range of 0.17-0.48. Parametric investigations are undertaken for constant chord length & span and varying turning angles of 5° 10° & 15°. Experimental resistance values in towing tank tests were validated with CFD. Investigations revealed that pressure increased as the flow velocity decreased with an increase in flap turning angle which was due to the centrifugal action of the flow caused by the induced concave curvature under the flap. There was no significant change in stern wave height but there was a gradual increase in the stern wave steepness with flap angle. Effective length of the vessel increased by lengthening of transom hollow. In low Froude number regime, flow was not influenced by flap curvature effects and pressure recovery was marginal. In the intermediate and high Froude number regimes pressure recovery increased with the flap turning angle and flow velocity.

• 한국군사과학기술학회지
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• 제21권1호
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• pp.103-114
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• 2018

The operational concept of control systems on surface combatants has been changed from individual control for each system to integrated control for all systems due to computing technology development and crew reduction policy of navy. The purpose of this study is to identify current status of control technology, to analyze user requirement and to develop an architecture to support the conceptual change of ship control. An architecture, which integrates several control and monitoring systems on naval surface combatant, is proposed. The proposed architecture is focused on sharing network and computing resources related to user command, and reducing systems complexity. The architecture can be adopted to next surface combatants in Korean navy.

• Ocean Systems Engineering
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• 제7권4호
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• pp.435-460
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• 2017

The main objective of this study is to investigate the turning and zig-zag maneuvering performance of the well-known naval surface combatant DTMB (David Taylor Model Basin) 5415 hull with URANS (Unsteady Reynolds-averaged Navier-Stokes) method. Numerical simulations of static drift tests have been performed by a commercial RANS solver based on a finite volume method (FVM) in an unsteady manner. The fluid flow is considered as 3-D, incompressible and fully turbulent. Hydrodynamic analyses have been carried out for a fixed Froude number 0.28. During the analyses, the free surface effects have been taken into account using VOF (Volume of Fluid) method and the hull is considered as fixed. First, the code has been validated with the available experimental data in literature. After validation, static drift, static rudder and drift and rudder tests have been simulated. The forces and moments acting on the hull have been computed with URANS approach. Numerical results have been applied to determine the hydrodynamic maneuvering coefficients, such as, velocity terms and rudder terms. The acceleration, angular velocity and cross-coupled terms have been taken from the available experimental data. A computer program has been developed to apply a fast maneuvering simulation technique. Abkowitz's non-linear mathematical model has been used to calculate the forces and moment acting on the hull during the maneuvering motion. Euler method on the other hand has been applied to solve the simultaneous differential equations. Turning and zig-zag maneuvering simulations have been carried out and the maneuvering characteristics have been determined and the numerical simulation results have been compared with the available data in literature. In addition, viscous effects have been investigated using Eulerian approach for several static drift cases.

• 대한조선학회논문집
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• 제57권5호
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• pp.262-270
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• 2020

An outdoor free-running model test system was designed for assessing ship maneuverability with test uncertainty. The test model was a surface combatant of tumblehome hull geometry. The straight forward tests were conducted first to obtain the relationship between the propeller revolution rate and advance speed. During the outdoor tests, the propeller revolution rate to achieve a certain Froude number condition was higher than that in the indoor free-running model tests. Turning circle and zigzag tests for evaluating ship maneuverability criteria were carried out at the propeller revolution rate determined by the straight forward test results. The random and systematic standard uncertainties of maneuvering criteria were obtained by repeated tests and comparison with the indoor free-running model test results, respectively. The test uncertainty was largely dominated by the systematic standard uncertainty, while the random standard uncertainty was small with good repeatability.

• 한국해양공학회지
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• 제26권3호
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• pp.13-19
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• 2012

Recently, as the importance of the interior noise in a ship cabin has risen, ship builders have becomeconcerned about the use of noise reduction panels to reduce cabin noise. The results of previous researches have been based on analytical and experimental methods using simple sandwich panels. However, panel structures are becoming more complex to improve the transmission loss. Thus, researches that analyze the transmission loss of a panel are reaching the limit of study. This paper reports on research that was performed to determine the sound transmission characteristics of multi-complex panels applicable to high value-added vessels. It presents comparisons between analytical methods and experimental results by using a mini-reverberant chamber with components of sound attenuation panels, including the core and surface materials. The sound transmission loss of multi-complex panels are also analyzed in terms of the influences of the inside perforate plates and air gap thickness on the attenuation. Finally, the multi-complex panel with the highest noise attenuation is proposed based on the analysis results and experimental results in mini-reverberant chamber, which wereverified using a real-size reverberant chamber.